CN115235417A - Monitoring point setting method based on angle between stacked tunnels - Google Patents

Abstract

The present invention relates to a method for setting monitoring points based on the angle between stacked tunnels. The method includes at least: determining the setting of monitoring points based on the clear spacing and/or angle between stacked tunnels corresponding to the monitoring section. The number and distribution range of the monitoring points of the monitoring section, wherein, when the angle between the two stacking tunnels is in the range of 40° to 60°, if the clear distance between the two tunnels is fixed, as the distance between the two stacking tunnels is fixed. To reduce the angle between the two, set up more monitoring points within the range of settlement influence, and increase the detection frequency. In view of the defect in the prior art that the number of monitoring points on each monitoring surface is greater than five and leads to a large number of invalid data, the present invention is based on the clear spacing and/or angle between the stacked tunnels corresponding to the monitoring sections. The number of monitoring points on the cross-section reduces the arrangement of invalid monitoring points, and reduces the collection and storage of a large amount of invalid data.

Description

A monitoring point setting method based on the angle between stacked tunnels

The application number is 202210327480.7, the application date is March 31, 2022, the name of the invention is a device and method for monitoring the complete stacking section of an upper and lower stacking tunnel, and the patent type is a divisional application of the patent application for invention.

technical field

The invention relates to the technical field of stacked tunnel construction, in particular to a monitoring point setting method based on the angle between stacked tunnels.

Background technique

The disturbance to the surface of the subway tunnel construction is unavoidable. Among the various construction methods, the shield construction method has relatively little disturbance to the surface. Since most of the subway construction is located in the relatively prosperous and densely populated areas of the city, the surface deformation is greater than the deformation critical value. The surrounding high-rise buildings, roads, underground pipelines, etc. have a great impact, so it is particularly important to monitor the shield tunnel section to feedback the construction.

With the development and utilization of underground space, more and more tunnels begin to be arranged in the upper and lower layers. However, the impact range and size of the shield construction on the upper surface are completely different from those of normal parallel tunnels, and there is no existing experience to refer to. .

In the process of shield tunneling, its superstructure or people will be affected by the vibration of the foundation or the surface and the secondary vibration caused by it, which will especially affect the structural safety of ancient and old buildings. , may make the human body feel different degrees of discomfort and affect people's health and interfere with people's normal life, especially when the upward tunnel construction has a greater impact on the upper part.

The prior art discloses some related technical solutions, but does not solve the above technical problems.

For example, Chinese patent document CN103277110 A discloses a construction method of a stacked shield tunnel. The construction steps include: excavation and construction of a downward shield tunnel, and the tunnel structure adopts a reinforced segment; the downward tunnel passes through a secondary grouting hole. The grouting pipe is used for grouting the sandwiched soil between the upward tunnel and the downward tunnel; before the construction of the upward tunnel, a trolley support system is set in the downward tunnel to protect the downward tunnel; during the construction of the upward shield tunnel, the downward tunnel is constructed during the construction. The supporting trolley keeps following up with the tunnel excavation; the ascending tunnel is grouted to the sandwiched soil between the ascending tunnel and the descending tunnel through the grouting pipe in the secondary grouting hole.

For example, Chinese patent document CN105332710 A discloses a construction method for upper and lower overlapping tunnels with small clear spacing and long distances in soft geology. The tunnel, the upper tunnel and the lower tunnel are all formed by segmented tunnel structures respectively. The vertical clear distance between the upper tunnel and the lower tunnel is less than 0.7D (shield diameter), and the length of the tunnel is greater than 1000m. The construction method is to complete the lower tunnel according to the conventional shield construction method, through the shield high-altitude starting platform, the upper and lower tunnel interlayer soil deep hole grouting reinforcement, the lower tunnel supporting steel ring reinforcement, the shield high-altitude receiving platform and other measures. To reduce the impact of the shield construction of the upper tunnel on the forming of the lower tunnel and the secondary superposition effect of the overlapping tunnel settlement, to ensure that the deformation and ground settlement of the lower tunnel are controllable.

None of the above-mentioned prior art involves the problem of burying the monitoring points of the completely overlapping section, and therefore does not solve the problem proposed by the present invention: how to monitor and reduce the vibration influence of the construction of the overlapping tunnel.

In addition, on the one hand, there are differences in the understanding of those skilled in the art; on the other hand, because the applicant has studied a large number of documents and patents when making the present invention, but due to space limitations, all details and contents are not listed in detail, but this is by no means The present invention does not possess the features of the prior art, on the contrary, the present invention already possesses all the features of the prior art, and the applicant reserves the right to add relevant prior art to the background art.

SUMMARY OF THE INVENTION

In view of the deficiencies of the prior art, the present invention provides a method for monitoring the complete overlapping section of an upper and lower overlapping tunnel. Based on the overlapping degree between the overlapping tunnels, at least one vertical axis perpendicular to the axis of the overlapping tunnel is selected. As the monitoring section of the stacked tunnel, the number of monitoring points set on the monitoring section is determined based on the clear distance and/or angle between the stacked tunnels corresponding to the monitoring section, and based on the monitoring points sent The settlement data are processed and analyzed.

The present invention monitors the influence of the surface subsidence caused by the construction of the stacked-drop tunnel in the whole process, and not only can collect the data of the surface subsidence caused by the first-start tunnel, but also can monitor the influence of the latter-start tunnel on the first-start tunnel and the surface settlement. Through the selection of monitoring sections and the arrangement of monitoring points, the lateral settlement data from one monitoring section to another monitoring section and the longitudinal monitoring data of monitoring points arranged along the monitoring section can be collected to form a three-dimensional monitoring, and the detection results are more accurate. .

Preferably, the stacking degree is related to the horizontal distance, vertical distance and radius of the tunnel axis between at least two tunnels, S=(L, H, R ₁ , R ₂ ), wherein S represents the stacking degree, L represents the horizontal distance of the tunnel axis, H represents the vertical distance of the tunnel axis, R ₁ represents the radius of the first tunnel, and R ₂ represents the radius of the second tunnel.

Preferably, the clear spacing and/or angle between the stacked tunnels is related to the maximum settlement value,

The number and distribution of monitoring points are set based on the correlation between the clear spacing and/or angle between the tunnels and the maximum settlement value.

Preferably, the method further comprises: adjusting the frequency of collection of settlement data based on changes in the first and/or second distances between the driving face and the monitoring section.

Preferably, when the first and/or second distances between the driving face and the monitoring section are not greater than the first threshold, the collection frequency of the settlement data is the first frequency; when the first and/or second distances between the driving face and the monitoring section are Or when the second distance is greater than the first threshold and not greater than the second threshold, the collection frequency of the settlement data is the second frequency; when the first and/or second distance between the driving surface and the monitoring section is greater than the second threshold, the settlement is The frequency of data collection is the third frequency.

Preferably, the method further comprises: adjusting the collection frequency of the subsidence data to a fourth frequency under the condition that the surface subsidence is stable.

Preferably, the method further comprises: in the case of abnormal ground subsidence, increasing the frequency of collecting subsidence data.

The invention dynamically adjusts the data collection frequency of each monitoring section based on the change of the excavation surface, improves the effective utilization of the data, and reduces the collection of data that has little effect on data analysis.

Preferably, the method further comprises: predicting the maximum subsidence amount based on a subsidence-time distribution fitting curve of surface subsidence.

Preferably, the conditions for the surface subsidence to be stable at least include:

The subsidence speed of road and surface has a clear trend of slowing down;

The convergence speed of road and surface subsidence is less than 0.01～0.04mm/day;

The amount of convergence reaches 80% and above of the total amount of convergence.

By predicting the maximum settlement amount, the present invention can reinforce the parts with large settlement, so as to ensure the normal progress of the shield construction process and prevent the surrounding buildings from being greatly affected. The present invention can monitor the whole process in the whole construction process, and can avoid large construction hidden dangers in the construction process with small capital investment.

The present invention also provides a monitoring device for a complete stacking section of an upper and lower stacking tunnel, which includes at least a number of monitoring units, the monitoring units are buried underground to form monitoring points for monitoring surface subsidence, and the monitoring sections where the monitoring points are located are based on stacking. At least one vertical plane perpendicular to the axis of the stacked tunnel is selected for the overlapping degree between the drop tunnels, and the number of the monitoring points in the monitoring section is based on the stacked drop corresponding to the monitoring section. Clear spacing and/or angle between tunnels. The monitoring unit is a sensor capable of monitoring surface subsidence.

The monitoring device of the present invention only needs to bury the monitoring point once, and can monitor the surface subsidence caused by successively starting tunnels, forming a three-dimensional monitoring, and through the processing and analysis of the data, combined with the specific construction situation, can determine the cause of the surface subsidence. and take relevant measures to reduce the surface subsidence, and at the same time, it can monitor the whole process, further enhance the effect of informatization construction, provide communication channels for construction and supervision units, evaluate the safety status of the soil, and put forward reasonable construction suggestions and measures , in order to ensure the safe construction of the subway project.

The present invention also provides a method for setting monitoring points based on the angle between the stacked tunnels, the method at least comprising: determining the setting based on the clear distance and/or the angle between the stacked tunnels corresponding to the monitoring sections The number and distribution range of the monitoring points on the monitoring section, wherein, when the angle between the two stacking tunnels is in the range of 40° to 60°, if the clear distance between the two tunnels is fixed, with the two stacking falling tunnels. The angle between them is reduced, more monitoring points are set up within the range affected by the settlement, and the detection frequency is increased.

Preferably, the method further includes: when the angle between the two stacked tunnels is in the range of 40° to 60°, if the angle of the two tunnels remains unchanged, setting more monitoring points as the clear distance increases , the density and detection frequency of the monitoring points are correspondingly reduced.

Preferably, the method further includes: setting a first monitoring section with an angle of 0° between the two stacked tunnels, and setting two or four monitoring points on the first monitoring section.

Preferably, the method further includes: monitoring the surface subsidence caused by the first-start tunnel during the shield tunneling process and collecting relevant data of the surface subsidence; monitoring the secondary vibration effect caused by the second-start tunnel during the shield tunneling process and collecting the surface subsidence The frequency of collection of settlement data is adjusted based on changes in the first and/or second distances between the driving face and the monitoring section.

Preferably, the method further includes: when the first and/or second distances between the driving surface and the monitoring section are not greater than a first threshold, the collection frequency of the settlement data is the first frequency; When the first and/or second distances are greater than the first threshold and not greater than the second threshold, the collection frequency of the settlement data is the second frequency; the first and/or second distances between the driving surface and the monitoring section are greater than the second At the threshold, the collection frequency of sedimentation data is the third frequency.

Preferably, the method further includes: when the surface subsidence is stable, adjusting the collection frequency of the subsidence data to a fourth frequency; the fourth frequency is once a month.

Preferably, the method further comprises: predicting the maximum subsidence amount based on the subsidence-time distribution fitting curve of the surface subsidence, and in the case of abnormal surface subsidence, the collection frequency of the subsidence data is increased.

Preferably, the method further includes: the conditions for the surface subsidence to be stable at least include:

The subsidence speed of road and surface has a clear trend of slowing down; the convergence speed of road and surface subsidence is less than 0.01-0.04mm/day; the convergence amount reaches 80% and above of the total convergence amount.

Preferably, the first threshold is 20m, and the first frequency is once a day; the second threshold is 50m, and the second frequency is once every two days; and the third frequency is once a week.

Preferably, a total of 6 monitoring sections are set in the stacking section; the first monitoring section is set with four monitoring points, the second monitoring section is set with twelve monitoring points, the third monitoring section is set with two monitoring points, and the fourth monitoring section is set with two monitoring points. Fourteen monitoring points are set on the monitoring section, two monitoring points are set on the fifth monitoring section, and two monitoring points are set on the sixth monitoring section.

Description of drawings

Fig. 1 is a schematic diagram of the layout of the monitoring points of surface subsidence in the stacking section provided by the present invention;

Fig. 2 is the buried schematic diagram of the reference point provided by the present invention;

Fig. 3 is the enlarged schematic diagram of the monitoring work base point provided by the present invention;

Fig. 4 is a schematic diagram of a stacking degree dividing element provided by the present invention;

Fig. 5 is the schematic diagram of the settlement curve of each monitoring section provided by the present invention;

6 is a schematic diagram of the longitudinal settlement of the first tunnel construction D1 section provided by the present invention;

7 is a schematic diagram of the longitudinal settlement of the first tunnel construction D2 section provided by the present invention;

8 is a schematic diagram of the longitudinal settlement of the first tunnel construction D3 section provided by the present invention;

9 is a schematic diagram of the longitudinal settlement of the first tunnel construction D4 section provided by the present invention;

10 is a schematic diagram of the longitudinal settlement of the first tunnel construction D5 section provided by the present invention;

Figure 11 is a schematic diagram of the longitudinal settlement of the first tunnel construction D6 section provided by the present invention.

List of reference signs

1: The first tunnel; 2: The second tunnel; 101: Protection pipe; 102: Outer pipe; 103: Hanging clip; 104: Benchmark; 105: Drill hole; 106: Base point; One monitoring point; DB1-4: the fourth monitoring point of the first monitoring section; DB2-1: the first monitoring point of the second monitoring section; DB2-12: the twelfth monitoring point of the second monitoring section; DB3-1: the third monitoring point The first monitoring point of the monitoring section; DB3-2: the second monitoring point of the third monitoring section; DB4-1: the first monitoring point of the fourth monitoring section; DB4-14: the fourteenth monitoring point of the fourth monitoring section; DB5-1 : the first monitoring point of the fifth monitoring section; DB5-2: the second monitoring point of the fifth monitoring section; DB6-1: the first monitoring point of the sixth monitoring section; DB6-2: the second monitoring point of the sixth monitoring section.

Detailed ways

The following detailed description is given in conjunction with the accompanying drawings.

Based on the deficiencies of the prior art, the present invention provides a method and device for monitoring the complete overlapping section of an upper and lower overlapping tunnel. The present invention can also provide a dynamic three-dimensional monitoring method and device for a fully stacked section of a stacked tunnel.

The method for monitoring the complete overlapping section of the upper and lower stacked tunnels of the present invention at least includes: selecting at least one vertical plane perpendicular to the axis of the stacked tunnel based on the stacking degree between the stacked tunnels as the vertical plane of the stacked tunnel. For the monitoring section, the number of monitoring points set on the monitoring section is determined based on the clear spacing and/or angle between the stacked tunnels corresponding to the monitoring section, and settlement data processing and analysis are performed based on the settlement data sent by the monitoring points.

The monitoring section where the monitoring point is located is determined according to the actual needs of the project.

The degree of stacking is related to the horizontal distance, vertical distance and radius of the tunnel axis between at least two tunnels. As shown in Figure 4, S=(L, H, R ₁ , R ₂ ), where S represents the stacking degree, L represents the horizontal distance of the tunnel axis, H represents the vertical distance of the tunnel axis, and R ₁ represents the first tunnel , and R2 represents the radius of the _second tunnel.

The number of monitoring points set on the monitoring section is determined based on the clear spacing and/or angle between the stacked tunnels.

The clear spacing and/or angle between stacked tunnels is related to the maximum settlement value. The number and distribution of monitoring points are therefore set based on the correlation between the clear spacing and/or angle between the tunnels and the maximum settlement value.

为2m。净间距指两个隧道横断面隧道中心连线的长度减去一个隧道直径的长度。Specifically, the number of monitoring points of the monitoring section is set according to the following clear distances and/or angles. In the present invention, the tunnel diameter is set to D,

is 2m. The clear distance refers to the length of the line connecting the center of the two tunnel cross-sections minus the length of one tunnel diameter.

When the shallow-buried double-hole tunnels are arranged horizontally and the clear distance between the two tunnels is small, the mutual influence between them is particularly great.

时，地表沉降最大值会突降很多，此时隧道的设计施工将会冒很大风险，应避免设计如此小间距工况。When the clear spacing is less than

At this time, the maximum surface settlement will suddenly drop a lot. At this time, the design and construction of the tunnel will take great risks, and the design of such small spacing conditions should be avoided.

时，随着净间距的增大，地表沉降最大值逐渐降低。When the clear spacing is greater than

, with the increase of the net distance, the maximum surface subsidence decreases gradually.

When the distance between the two tunnels is small, as the angle increases, the maximum surface subsidence decreases rapidly, and it is less sensitive to the change of the arrangement angle in the area where the clear distance is 9-15m.

这一区间内，地表沉降最大值对布置角度的改变特别敏感，应尽量避免在此区域内改变两隧道的布置角度。The clear spacing is

In this interval, the maximum surface settlement is particularly sensitive to the change of the arrangement angle, and it should be avoided as much as possible to change the arrangement angle of the two tunnels in this area.

When the net distance is less than D, the maximum surface subsidence is sensitive to the angle. With the increase of the clear distance, the mutual influence of the angle on the two tunnels gradually decreases.

In the range of angle 40°～60°, the mutual influence between double-hole tunnels is relatively large, especially for small-spacing double-hole tunnels.

If the clear distance between the two tunnels is fixed, as the angle between the two tunnels decreases, the maximum settlement value will gradually increase, but the range of settlement influence is small, so more monitoring points can be set up in a small range, and additional High detection frequency.

Correspondingly, if the angle of the two tunnels remains unchanged, with the increase of the clear distance, the settlement will be reduced accordingly, but the scope affected by the construction is wide, and more monitoring points need to be set up. The density and detection frequency of the monitoring points are set. can also be reduced accordingly.

When the clear distance between the two tunnels is small and the angle between the two tunnels is between 40-60, it is not only necessary to set up multiple monitoring points in a small range, but also to increase the detection frequency.

As shown in Figure 1, the first and second lines of a subway tunnel in a certain city are arranged in a stacked arrangement and constructed by the shield method. The second tunnel is located below, and the soil layer passing through the stacking section is mainly sand and pebble layer, with a buried depth of 21.5-23.7m, and the groundwater is mainly interlayer phreatic water and confined water. The first tunnel is located above, mainly through the soil layer of silty clay layer. The buried depth of the first tunnel is 13.8-15.3m. The groundwater is mainly phreatic and interlayer phreatic. The vertical distance of the tunnel in the stacking section is 1.95-3.3m.

A total of 36 settlement monitoring points are set up on the surface of the fully overlapping section of the shield tunnel. There are a total of 18 monitoring points in the first line of the Dieluo section crossing the silty clay section, and a total of 18 monitoring points in the second line's Dieluo section crossing the sand and pebble section, with a monitoring accuracy of 1.0mm.

There are 6 monitoring sections in the stacking section. From the right to the left of FIG. 1 are the first monitoring section, the second monitoring section, the third monitoring section, the fourth monitoring section, the fifth monitoring section and the sixth monitoring section.

The first monitoring section is provided with four monitoring points, including first monitoring points DB1-1 to DB-1-4 on the first monitoring section. In FIG. 1, only the first monitoring point DB1-1 of the first monitoring section and the fourth monitoring point DB-1-4 of the first monitoring section are marked.

The second monitoring section is provided with twelve monitoring points, as shown in FIG. 1 and FIG. 7 , including the first monitoring points DB2-1 to DB2-12 on the second monitoring section. In FIG. 1, only the first monitoring point DB2-1 of the second monitoring section and the twelfth monitoring point DB2-12 of the second monitoring section are marked.

The third monitoring section is provided with two monitoring points, as shown in FIG. 1 and FIG. 8 , including the first monitoring point DB3-1 of the third monitoring section to the second monitoring point DB3-2 of the third monitoring section.

The fourth monitoring section is provided with fourteen monitoring points, as shown in Figures 1 and 9, including the first monitoring points DB4-1 to DB4-14 on the fourth monitoring section. Only the first monitoring point DB4-1 of the fourth monitoring section and the fourteenth monitoring point DB4-14 of the fourth monitoring section are marked in FIG. 1 .

The fifth monitoring section is provided with two monitoring points, as shown in FIG. 1 and FIG. 10 , including the first monitoring point DB5-1 of the fifth monitoring section and the second monitoring point DB5-2 of the fifth monitoring section.

The sixth monitoring section is provided with two monitoring points, including the first monitoring point DB6-1 of the sixth monitoring section and the second monitoring point DB6-2 of the sixth monitoring section.

For example, in the first monitoring section, the angle of the two tunnels is 0, and the final settlement caused by the construction is large, but the upper and lower arrangement has a smaller span than the left and right arrangement, the scope affected by the construction is small, and the clear distance between the two tunnels is large. In addition, the first monitoring section is located in the cultural relics protection zone, and it is not allowed to set detection points, so two monitoring points are set up on this monitoring section. The frequency of detection is appropriately increased during monitoring.

In the fourth monitoring section, the angle of the two tunnels is in a relatively sensitive range, and the clear distance between the two tunnels is small, so it is necessary to set up several more monitoring points in the fourth monitoring section. The present invention sets 14 monitoring points, and the detection frequency needs to be increased.

In the monitoring points of the same monitoring section, the buried depth is the same.

The reference point must be buried outside the construction influence area (50m), and the reference point must be buried in the stratum below the influence depth of the soil settlement caused by the construction. As shown in Figure 3, the work reference point adopts the cement observation pier with forced centering, and each survey area is not less than 3, so as to check each other.

In the present invention, the reference point is a standard reference point whose elevation is known. During monitoring, by measuring the elevation difference between each monitoring point and the benchmarking point (base point), the standard elevation of each monitoring point can be obtained, and then compared with the last measured elevation, the difference is the settlement value of the measuring point.

FIG. 2 shows a schematic diagram of the burial of the monitored reference points of the present invention. As shown in FIG. 2 , the way of burying the reference point includes: excavating a hole 105 with a diameter of 200 mm with a drilling machine, and then lowering the protection pipe 101 after the hole is completely cleared. An outer tube 102 and a post 104 are provided within the bore hole 105 . Clay is backfilled between the walls of the protective tube 101 and the outer tube 102 . The reference point protection base 106 and the pole 104 are taken into the protection tube 101 . The protective base 106 is cemented. The top is made into a spherical shape, and the protective cover of the measuring point is made.

The effectiveness of monitoring the surface subsidence of the Die-luo section of the Die-luo tunnel is directly related to the selected monitoring method and the arrangement of the measuring points. The monitoring work is based on the premise of on-site safety management and monitoring. The location and number of points should be comprehensively considered in combination with factors such as geological conditions, stratum properties, construction technology, surface surrounding environment and monitoring costs. The location of the surface monitoring points should firstly ensure that the deformation characteristics of the surface are well reflected, and it should be convenient for instrument observation, and the damage of the monitoring points should be avoided as much as possible by external factors.

Therefore, the burying of monitoring points should adopt the standard method and the shallow setting method. Monitoring points are used to collect subsidence data of surface subsidence.

Standard burying method: first, open a hole of Φ100mm on the ground, and drive in the Φ22mm threaded steel bar ground into an oval at the top. Then, fill in fine sand around the marking steel bars to tamp, and finally make an iron cover on the upper part of the monitoring point to protect it. For the sections where the existence of voids in the ground and the subsidence during construction are detected in advance, standard methods are used to bury the surface subsidence observation points.

The shallow setting method is as follows: first, drill a hole with a depth of about 20cm and a diameter of 12cm with an impact drill on the ground, then put a φ8mm round steel with a convex spherical surface on the top into the hole, and fill the gap with an anchoring agent.

The surface subsidence control index is the deformation control index. The monitoring and control standards are: the maximum allowable settlement value is 30mm, the maximum allowable deformation rate is 4mm/d, and the surface uplift control value is 10mm. Road and surface settlement monitoring and measurement points should be buried flat to prevent people and vehicles from being affected by unevenness. At the same time, the monitoring points should be firmly buried and clearly marked for easy storage.

After the monitoring points are set, the present invention starts to monitor the ground subsidence during the construction process. The first originating tunnel is the second tunnel 2 , and the latter originating tunnel is the first tunnel 1 . The first distance is the distance between the driving face of the shield and the monitoring section located in front of the shield. The second distance is the distance between the driving face of the shield and the monitoring section behind the shield.

First, monitor the surface subsidence caused by the first-start tunnel during the shield tunneling process, and collect relevant data on surface subsidence.

Second, monitor the impact of secondary vibration caused by the shielding process of the initial tunnel, and collect relevant data on surface subsidence.

The frequency of collection of settlement data is adjusted based on changes in the first and/or second distances of the advancing face and the monitoring section.

Specifically, when the first and/or second distances between the driving surface and the monitoring section are not greater than the first threshold, the collection frequency of the settlement data of the monitoring section is the first frequency. The first threshold is 20m and the first frequency is once a day.

When the first and/or second distance between the driving face and the monitoring section is greater than the first threshold and not greater than the second threshold, the collection frequency of the settlement data of the monitoring section is the second frequency. The second threshold is 50m and the second frequency is once every two days.

When the first and/or second distances between the driving face and the monitoring section are greater than the second threshold, the collection frequency of the settlement data of the monitoring section is the third frequency. The third frequency is once a week.

That is, with the change of the excavation surface of the shield, the collection frequency of the settlement data of each monitoring section also changes, and the collection frequency of the monitoring points of each monitoring section is different. Compared with the method of collecting sedimentation data at the same frequency at each monitoring point in the prior art, the method of adjusting the frequency of collecting sedimentation data of the present invention can reduce the collection and storage of a large amount of invalid data.

Preferably, the sedimentation is analyzed from the data. When the surface subsidence is stable, the collection frequency of subsidence data is adjusted to be the fourth frequency. The fourth frequency is monthly.

The conditions for surface subsidence to stabilize include at least:

The subsidence speed of road and surface has a clear trend of slowing down;

The convergence speed of road and surface subsidence is less than 0.01～0.04mm/day;

The amount of convergence reaches 80% and above of the total amount of convergence.

In the case of abnormal surface subsidence, the frequency of collection of subsidence data increases.

Preferably, each time the on-site monitoring work is carried out, on-site safety inspections are carried out at the same time, and inspections are guaranteed once a day, and the inspection video rate should be increased in special circumstances.

The original data obtained by on-site measurement has a certain discreteness, including the influence of accidental errors, so the present invention selects the discrete graph of the settlement-time curve for processing. After collecting the data of the surface subsidence, the present invention analyzes the data based on the subsidence-time distribution fitting curve of the surface subsidence, and predicts the maximum subsidence amount.

According to the measured road and ground subsidence values, the present invention judges whether the road and ground subsidence exceeds the safety control standard and the reliability of the adopted engineering measures. Compare the stage deformation rate and deformation amount with the control standard, and judge the early warning status of the monitoring point. If the data shows that the warning standard is met, and the analysis confirms that there is an abnormal situation, the detection frequency should be encrypted, and relevant processing should be done in time.

Through the processing and analysis of the data, the present invention can judge the cause of the surface subsidence and take relevant measures to reduce the surface subsidence in combination with the specific construction situation. Not only that, the present invention can monitor the whole process at the same time, and further enhance the effect of informatization construction.

Specifically, the processing and analysis of the monitoring data of the present invention are as follows.

The surface subsidence caused by the first-initiated tunnel during the shield tunneling process was monitored, and the relevant data of the surface subsidence were collected and analyzed. The fitting curve of the subsidence-time distribution is shown in Figure 5.

The shield of the first tunnel is being prepared before construction, and the second tunnel has been constructed to the 348th ring. At this time, the surface deformation of the stacking section caused by the construction of the second line of shields has basically ended. Monitoring the first to sixth The section is continuously monitored until the settlement is basically stable.

As shown in Figure 5, the maximum settlement at the second monitoring section is 5.93mm, which is slightly smaller than that of other monitoring sections. This is due to the fact that the second monitoring section is in the shield initiation stage, the shield advancement speed is slow, and the reinforcement effect of the initiation end is good.

It can be seen from Figure 5 that the settlement curves of the first and second monitoring sections are distributed asymmetrically along the center of the tunnel. The maximum settlement of each monitoring section occurs on the tunnel centerline, and gradually decreases along the lateral direction of the tunnel and is far from the axis. There are small uplifts on the surface of the area, with an average of less than 2mm.

According to the above monitoring results, the settlement value of the first and second monitoring sections whose overlying soil is silty clay is generally lower than that of the third, fourth, fifth and sixth monitoring sections whose overlying soil is sand and pebble strata. The average settlement value at the first and second monitoring sections is about 7mm. The average settlement value of the other four monitoring sections is about 12mm. Under the same construction conditions, the surface subsidence of the overlying soil is silty clay is slightly smaller than that of the sand-cobble layer.

According to the monitoring results in Figure 5, when the third, fifth, and sixth monitoring sections pass through the soil layer and the properties of the overlying soil are basically the same, the average settlement increases sequentially. This is because the buried depth of the tunnel keeps decreasing along the tunneling direction due to small.

It can be seen from Figure 5 that the settlement monitoring points 43 and 44 of the fourth monitoring section have large fluctuations, which may be due to construction or damage to the monitoring points.

The overall monitoring results show that the maximum subsidence of the stacking section occurs in the fourth monitoring section, and the maximum subsidence is 19.08mm. Within the design allowable range, the settlement of other monitoring sections is less than 15.00mm. During the on-site inspection process, the construction parameters of the shield were appropriate, the posture of the shield was good, and there was no need for major deviation correction.

After monitoring the impact of secondary vibration caused by the shielding process of the initial tunnel, the relevant data of the surface subsidence was collected.

The construction of the first tunnel 1 produced secondary disturbance to the stratum, causing secondary subsidence of the surface, and then the six monitoring sections from the first to the sixth were monitored until the surface subsidence was basically stable.

According to Figure 6 and Figure 7, it can be seen that the construction of the first tunnel causes the surface to rise first and then settle. This is due to the good reinforcement effect of the second tunnel. Upward bulge trend. When the shield passes through the monitoring point, the surrounding soil loses the support of the shield shell, and is replaced by the unsolidified or incompletely solidified slurry, and the surface tends to settle. After the shield passes through, the secondary slurry replenishment is carried out in time, and the surface settlement is gradually stabilized. It can be seen from Figure 2 and Figure 3 that the maximum subsidence value of the first monitoring section is 8.45mm, and the maximum subsidence value of the second monitoring section is 12.35mm, which has a better control effect on the surface subsidence.

As indicated in 8 and 9, the settlement law of the third monitoring section is different from the settlement law of the second monitoring section. During the construction of the first tunnel, the third monitoring section had no tendency to bulge, and the subsidence started when the shield reached the monitoring point. During the advancement of the shield, the subsidence of the third monitoring section continued to increase, the subsidence rate was relatively large, and the surface subsidence obviously had a tendency to exceed the specified value of 30mm. On October 15th, the grouting slurry was simultaneously replaced with cement-water glass slurry, and the double-liquid slurry was used for secondary slurry replenishment in time for the areas with excessive settlement rate, which basically controlled the problem of excessive settlement rate, but the third The maximum settlement of the monitoring section still reaches 34.26mm.

The surface subsidence of the third monitoring section exceeds the surface subsidence of the second monitoring section by a large amount. After summarizing the analysis, it is concluded that the reason for the excessive settlement of the third monitoring section is that the interlayer soil between the first and second tunnels in the third monitoring section is not reinforced, resulting in excessive settlement. The second monitoring section was not reinforced with interlayer soil and did not experience large settlement, because the second monitoring section passed through the soil layer mainly silty clay layer, and no interlayer soil reinforcement was required when crossing the silty clay layer. However, the third monitoring section crosses the soil layer mainly with sand and pebble layers, and the sand and pebble layers need to be reinforced with interlayer soil.

It can be seen from Fig. 9 that the maximum subsidence of the fourth monitoring section is 23.22mm, relatively speaking, the surface subsidence control effect is good, and there is a tendency of uplift and then subsidence in the advance, which is similar to the subsidence law of the second monitoring section. The control effect of the surface settlement of the fourth monitoring section is better than that of the third monitoring section, which is due to the reinforcement of the soil between the upper and lower caverns. It can be seen that the interlayer soil does not need to be reinforced when the shield tunneling soil is a silty clay layer, and the interlayer soil needs to be reinforced when the shield tunneling soil is a sandy pebble layer.

It can be seen from Figure 10 that in the process of shield tunneling, the surface has a tendency to uplift first, but from October 26 to October 28, the surface subsidence rate was too large, and the maximum subsidence rate reached 4 mm/day. From October 29, the surface subsidence rate decreased and the surface subsidence tended to be stable. The site survey found that from October 26th to October 28th, due to the failure of the shield machine, the advance was stopped, and on October 29th the shield machine resumed normal advance. Before the shield machine stopped advancing, although the excavation volume was reduced and the earth pressure in the soil tank was slightly larger than the set earth pressure, the downtime was long, and no other measures were taken to prevent the shield from retreating, resulting in the downtime during the downtime. , the surface subsidence rate is too high.

It can be seen from Figure 11 that the maximum subsidence of the surface of the sixth monitoring section is 17.81mm, relatively speaking, the surface subsidence control effect is good, and there is a trend of first uplift and then subsidence in the advance, which is similar to the subsidence law of the second and fourth monitoring sections.

From the subsidence maps of the second, fourth, and sixth monitoring sections, it can be seen that the impact of shield tunnel advancement on the surface of the stacking section has a tendency of uplift and then subsidence. Not big, all within the allowable range of surface subsidence.

According to the subsidence maps of the second, fourth and sixth monitoring sections, the surface subsidence caused by the advancement of the lower tunnel accounts for 76.65% of the total settlement, and the surface subsidence caused by the advancement of the upper tunnel accounts for 23.35% of the total settlement. %. From the subsidence maps of the third and fifth monitoring sections, the surface subsidence caused by the advancement of the lower tunnel accounts for 34.78% of the total settlement, and the surface subsidence caused by the advancement of the upper tunnel accounts for 65.22% of the total subsidence.

It can be seen that when the surface settlement of the upper tunnel is well controlled, the main cause of the surface subsidence is the advancement of the lower tunnel, while when the surface settlement control of the upper tunnel is not ideal, the main cause of the surface subsidence is the lower tunnel. advance. Therefore, in the advancement of the backward shield tunnel in the stacked-drop tunnel, the control measures of surface subsidence should be strengthened to minimize the secondary disturbance of the surface caused by the backward shield advancement.

It should be noted that the above-mentioned specific embodiments are exemplary, and those skilled in the art can come up with various solutions inspired by the disclosure of the present invention, and these solutions also belong to the disclosure scope of the present invention and fall within the scope of the present invention. within the scope of protection of the invention. It should be understood by those skilled in the art that the description of the present invention and the accompanying drawings are illustrative rather than limiting to the claims. The protection scope of the present invention is defined by the claims and their equivalents. The description of the present invention contains multiple inventive concepts, such as "preferably", "according to a preferred embodiment" or "optionally" all indicate that the corresponding paragraph discloses a separate concept, and the applicant reserves the right to propose divisions according to each inventive concept the right to apply.

Claims (10)

1. a monitoring point setting method based on the angle between the stacked tunnels, is characterized in that, the method at least comprises: The number and distribution range of monitoring points arranged on the monitoring section are determined based on the clear distance and/or angle between the stacked tunnels corresponding to the monitoring section, wherein, When the angle between the two stacked tunnels is in the range of 40° to 60°, if the clear distance between the two tunnels is fixed, as the angle between the two stacked tunnels decreases, a more More monitoring points, and increase the detection frequency. 2. The monitoring point setting method based on the angle between the stacked tunnels according to claim 1, wherein the method further comprises: When the angle between the two stacked tunnels is in the range of 40° to 60°, if the angle of the two tunnels remains unchanged, more monitoring points are set with the increase of the clear distance, and the density and The detection frequency is reduced accordingly. 3. The monitoring point setting method based on the angle between the stacked tunnels according to claim 2, wherein the method further comprises: A first monitoring section with an angle of 0° between the two stacked tunnels is provided with two or four monitoring points. 4. The monitoring point setting method based on the angle between the stacked tunnels according to any one of claims 1 to 3, wherein the method further comprises: Monitor the ground subsidence caused by the first-start tunnel during the shield tunneling process and collect relevant data on the ground subsidence; Monitor the secondary vibration effects caused by the shielding process of the initial tunnel and collect relevant data on surface subsidence; The frequency of collection of settlement data is adjusted based on changes in the first and/or second distances of the advancing face and the monitoring section. 5. The monitoring point setting method based on the angle between the stacked tunnels according to claim 4, wherein the method further comprises: When the first and/or second distance between the driving face and the monitoring section is not greater than the first threshold, the collection frequency of the settlement data is the first frequency; When the first and/or second distance between the driving surface and the monitoring section is greater than the first threshold and not greater than the second threshold, the collection frequency of the settlement data is the second frequency; When the first and/or second distances between the driving face and the monitoring section are greater than the second threshold, the frequency of collecting the settlement data is the third frequency. 6. The monitoring point setting method based on the angle between the stacked tunnels according to claim 5, wherein the method further comprises: In the case of stable surface subsidence, the collection frequency of subsidence data is adjusted to be the fourth frequency; the fourth frequency is once a month. 7. The monitoring point setting method based on the angle between the stacked tunnels according to claim 5, wherein the method further comprises: The maximum subsidence is predicted based on the subsidence-time distribution fitting curve of surface subsidence, In the case of abnormal surface subsidence, the frequency of collection of subsidence data increases. 8. The monitoring point setting method based on the angle between the stacked tunnels according to claim 5, wherein the method further comprises: The conditions for the surface subsidence to be stable at least include: The subsidence speed of road and surface has a clear trend of slowing down; The convergence speed of road and surface subsidence is less than 0.01～0.04mm/day; The amount of convergence reaches 80% and above of the total amount of convergence. 9. The monitoring point setting method based on the angle between the stacked tunnels according to claim 5, is characterized in that, The first threshold is 20m, and the first frequency is once a day; The second threshold is 50m, and the second frequency is once every two days; The third frequency is once a week. 10. The monitoring point setting method based on the angle between the stacked tunnels according to claim 5, characterized in that, A total of 6 monitoring sections are set in the stacking section; the first monitoring section is set with four monitoring points, the second monitoring section is set with twelve monitoring points, the third monitoring section is set with two monitoring points, and the fourth monitoring section is set with There are fourteen monitoring points, the fifth monitoring section has two monitoring points, and the sixth monitoring section has two monitoring points.

Images