RU2295607C2 - Ground consolidation method - Google Patents

Abstract

FIELD: building, particularly to consolidate motor road bed, paving or slopes.

SUBSTANCE: method involves serially treating ground with 20% aqueous saponified tall pitch mixed with waste oil from motor car engines at t=50-100°C up to emulsion obtaining and with 10% aqueous calcium chloride solution; leaving ground as it is to provide full polymerization and compacting ground under pressure of not less than 15.0 MPa. Ratio between saponified tall pitch and waste oil is 1.0:0.01-0.1. Ratio between above emulsion and aqueous calcium chloride solution is 1:0.28-0.3. The invention is disclosed in independent claims.

EFFECT: increased strength and frost-resistance of consolidated ground.

8 cl, 1 ex, 5 tbl

Description

The invention relates to construction and can be used to secure the foundations, coatings or slopes of roads.

A known method of fixing rocks, including sequential or simultaneous separate treatment of the rock in a stream of atmospheric air with diesel or oil alkaline waste oil and 5-30% solution of calcium or magnesium chloride in a ratio of 1.0: 0.3-1.0, respectively. If necessary, the breed is additionally compacted (RF patent No. 1794132, E 02 D 3/12, Method for fixing rocks / E.I. Zhirnov, B.A.Sotnik et al. - 4919128 from 03/14/91, publ. 07.02.93 Bull. No. 5).

The disadvantage of this method is the low strength of the fixed rocks and the high energy intensity associated with air consumption.

The closest in technical essence and the achieved result is a method of fixing the soil, including sequential processing of the soil with aqueous solutions of saponified melt pitch (OTP) and calcium chloride, and then injection into the soil of compressed air in an amount exceeding the volume of the gel-forming solution (A.S. USSR No. 1574729, E 02 D 3/12, Method of fixing the soil / MF Karimov and others - application No. 4241152 from 05/05/87, publ. 30.06.90 Bull. No. 24).

However, the known method has the following disadvantages:

1) when soil is treated with solutions of OTP and calcium chloride, a polymer instantly precipitates; and when air is injected, it is difficult to push the polymer through the pores of the soil, the radius of the fixed soil is 19.2 cm;

2) the resulting polymer has low adhesion properties to soil particles and contains free water, which, with a decrease in soil moisture, is removed from the polymer with significant shrinkage, leading to soil softening;

3) the resulting polymer is highly brittle and when exposed to dynamic loads, such as road vehicles, and at alternating temperatures, it softens and decreases frost resistance;

4) this method is complex and energy intensive.

The aim of the invention is to increase the strength and frost resistance of fortified soil.

This object is achieved in that in a method of strengthening the soil, which includes sequential soil treatment with aqueous solutions of saponified mealy pitch (OTP) and calcium chloride, before processing the soil, an aqueous solution of saponified mealy pitch is mixed with used motor oil from automobile engines at t = 50-100 ° C in a ratio of 1.0: 0.01-0.1 to obtain an emulsion, and after the introduction of calcium chloride, the soil is maintained until complete polymerization and compacted at a pressure of at least 15.0 MPa. Moreover, for the treatment of soil using a 10% solution of calcium chloride.

Soil before processing is loosened to a depth of processing.

To obtain the emulsion using a 20% solution of OTP. The emulsion consumption on the basis of saponified thawed pitch for soil processing is 0.08-0.25 kg / kg of soil, including 0.08-0.11 kg / kg of soil for processing incoherent soils; for processing cohesive soils 0.12-0.25 kg / kg of soil. And as a solution of calcium chloride, drainage brines are used.

Boundary limits of the quantitative content of used motor oil of automobile engines in the emulsion are justified experimentally. The data in table 4 gr. 7-9 (indicators of frost resistance and compressive and tensile strength when bending reinforced soil). The optimal ratio of a 20% solution of saponified taly pitch and used motor oil from automotive engines is 1: 0.055.

Saponified taly pitch (OTP) is a waste of pulp and paper production and under normal conditions it is a solid consistency product with a density of 0.95-1.0 g / cm ³ with a softening temperature of 60-75 ° C and corresponds to TU 13-0281078-146 -90 "Talc saponified sap". It is non-toxic, fireproof, convenient for transportation. Dissolving in fresh water, OTP forms a colloidal solution.

In the process of operation of automobile engines, engine oils that meet GOST 12337-84 "Engine oils for diesel engines" of the M-10G ₂ brand and GOST 10541-78 "Engine oils for carburetor engines" of the M-8B ₁ brand, under the influence of high temperatures and oxygen oxidized to form resins, asphaltenes, carbenes, impurities and water. After 250 engine operating hours, the engine oil is replaced. Table 1 shows the characteristics of used motor motor oils. For areas with complex transportation schemes, such as areas of the Far North, the return of used motor motor oils for regeneration is problematic. Their disposal in accordance with Clause 2, Article 51 of the Federal Law of the Russian Federation “On Environmental Protection” dated January 10, 2002 is prohibited. The use of waste oils in the preparation of OTP will allow, along with their utilization, to solve the problems of soil strengthening.

To obtain an emulsion based on solutions of saponified taly pitch and used motor oils from automobile engines, they are mechanically mixed at t = 50-100 ° C. At a mixing temperature of less than 50 ° C, the emulsion exfoliates during storage. The maximum heating temperature is limited by the boiling point of the emulsion. The choice of a 20% concentration of the OTP solution is due to the maximum dry matter flow rate to obtain a stable emulsion. When soil is treated successively with an emulsion and a CaCl ₂ solution, a polymer is formed with high adhesive, elastic properties that improves soil structure formation with the formation of a strong and frost-resistant structure. This is due to the fact that oil films slow down the process of soil polymerization in the initial stage of structure formation and technologically simplify the completeness of processing of soil particles with CaCl ₂ solution, because there is no instant salting out of the polymer.

The use of a 10% solution of CaCl ₂ is due to its penetration into the soil. Drainage brines, containing predominantly chloride salts of calcium, magnesium and sodium, are waste products in the development of kimberlite pipes and require disposal. Their use in methods for strengthening soils will help to resolve environmental issues in the region and reduce the cost of implementing the method.

With further compaction of the treated soil (pressure above 15.0 MPa), excess water is removed from the soil, and the binder - the polymer - is practically dehydrated, while maintaining high adhesive and elastic properties.

Soil before processing can be loosened to the depth of impregnation or processed without destroying the original structure of the soil, for example, to strengthen the slopes of roads, etc.

Specific implementation examples

Cohesive soil (loam) and incoherent soil (quartz sand) were tested as soil.

Soil characteristics

1. Cohesive soil (loam)

Table 1 Grain size distribution of loam Sieve, mm twenty fifteen 10 5 2,5 1.25 0.63 0.31 0.14 <0.14 Plasticity number Private balance,% 6 2 3 9 25.5 14.5 10.7 6.4 8.7 14.2 8

2. Non-cohesive soil (silica sand)

table 2 Granulometric composition of sand Sieve, mm 5 2,5 1.25 0.63 0.31 0.14 <0.14 Plasticity number Private balance,% fourteen 26.3 11,4 20.8 10.6 5.2 11.7 0

Soils were dried before the test.

As used motor oils for automobile engines, oils of the M-10G ₂ TsS and M-8B ₁ brands were used.

Table 3 Characteristics of used automotive engine oils The name of indicators Oil, % Resin,% Asphaltenes,% Carbenes,% Impurities,% Water% Spent motor oil grade M-10G ₂ 77.4 2.6 2.1 1,6 1,6 14.7 Used motor oil of brand M-8B ₁ 80.2 1.8 2,3 1.7 1.8 12,2

As calcium chloride solutions, a solution of calcium chloride or drainage brines of 10% concentration were used.

Composition of drainage brines:

CaCl ₂ - 80%, MgCl ₂ - 9%, NaCl - 11%.

As a binder component, saponified talc pitch, corresponding to TU 13-0281078-146-90 "Saponified talcum pitch" was used. A solution of saponified thawed pitch 20% concentration was prepared by mixing solid concentrate in hot water t = 80 ° C.

An emulsion based on saponified taly pitch was prepared by mixing spent motor oil of an automobile engine with t = 20 ° C in an amount of 0.008; 0.01; 0.055; 0.1; 0.12; kg per kg of solution of saponified thawed pitch with t = 70 ° C in a paddle mixer n = 600 rpm for 3 minutes. The prepared emulsion was poured into a separate container for storage and further use.

Table 4 shows the test results of the samples for strength and frost resistance depending on the amount of used motor oils of automobile engines in an emulsion based on OTP.

It was experimentally revealed that for the complete salting out of the polymer, the ratio of components: emulsion based on OTP and 10% CaCl ₂ is 1: 0.2. To completely impregnate the soil, a solution of calcium chloride was introduced in excess: 1: 0.28-0.3.

Soil treatment was carried out at a soil and binder temperature of 20 ° C in a laboratory paddle mixer; the soil was first mixed with OTP-based emulsion for 40 seconds, then with a 10% calcium chloride solution for 1 minute, and kept until polymerization was complete for 20 minutes.

Sample cylinders размером 72.5 × 72.5 mm in size and beam samples of 40 × 40 × 160 mm in size under a pressure of 15.0 MPa were made from the mixture. Water-saturated samples were tested after 7 days for compression and tension during bending. In addition, the cylinder samples were kept for 28 days in a humid environment before being tested for frost resistance. The coefficient of frost resistance was determined by reducing the strength of the samples under compression after 50 cycles of "freezing - thawing". Table 5 shows the test results of the samples for strength and frost resistance depending on the flow rate of the emulsion based on OTP and calcium chloride solution.

Based on the experimental data given in tables 4 and 5, we can draw the following conclusions.

When treating soils with an OTP-based emulsion (with a ratio of 1: 0.01-0.1) and a calcium chloride solution, the main indicators of fortified soils were achieved that exceed the regulatory requirements of SNiP 2.05.02-85 *. With a slight flow of waste motor oils automobile engines emulsions (formulations 1, 6, 11, 16), the compressive strength increases and thereafter remains unchanged, but the tensile strength in bending (R _mfd) and frost factor (K _MDE) below required by SNiP 2.05.02-85 *. When the boundary limits for the consumption of used motor oil of automobile engines in the emulsion (compositions 5, 10, 15, 20) increase, the tensile strength in bending (R _arg ) and the coefficient of frost resistance (K _mrz ) decrease below those required by SNiP, and the compressive strength decreases but remains higher than required by SNiP 2.05.02-85 * (Table 4).

At a flow rate of the emulsion for treating soils in an amount of 0.08-0.25 achieved indicators (R _{SJ mfd} R K _MDE) exceeding standard indicators SNP. With an increase in emulsion flow rate above the upper limit (compositions 5, 10, 15, 20, Table 5), humidity increases, which complicates the technology of compaction of soils when performing road construction works: before compaction, drying of the soil to permissible humidity is required. During the drying, the performance of soil samples exceeds the norm.

With a decrease in the emulsion flow rate below the lower limit (compositions 1, 6, Table 5), the tensile strength at bending (R _arg ) and the coefficient of frost resistance (K _mrz ) are lower than those required by SNiP 2.05.02-85 *. When treating cohesive soil with an OTP-based emulsion within the range of 0.08-0.1, the moisture content of the obtained samples is insufficient for compaction (Table 5).

Compared with the prototype, the strength characteristics and frost resistance of fortified soil by the proposed method is more than 2 times higher.

Table 4 Test results of samples for strength and frost resistance depending on the amount of waste oils in the emulsion Composition number The ratio of components in the emulsion, weight. h Component consumption, kg / kg of soil The strength of water-saturated samples, MPa Coefficient of frost resistance, K _mrz 20% rtr OTP brand waste oil OTP based emulsion 10% CaCl ₂ solution Compression, R _Comp tensile bending, R _mfd M-8B ₁ M-10G ₂ 7 days 7 days Ground sand one one 0.008 - 0,095 0.27 3.4 0.50 0.50 2 one 0.01 - 0,095 0.27 3.4 0.65 0.70 3 one 0,055 - 0,095 0.27 3.2 0.85 0.80 four one 0.1 - 0,095 0.27 2,8 0.70 0.70 5 one 0.12 - 0,095 0.27 2.0 0.55 0.55 6 one 0.08 0,095 0.27 3.4 0.52 0.52 7 one 0.01 0,095 0.27 3.4 0.60 0.62 8 one 0,055 0,095 0.27 3.2 0.80 0.78 9 one 0.1 0,095 0.27 2.6 0.65 0.70 10 one 0.12 0,095 0.27 2.1 0.55 0.50 prototype 0.8 0.13 0.3 Loamy soil  eleven one 0.008 - 0.18 0,054 4.0 0.55 0.58 12 one 0.01 - 0.18 0,054 3.8 0.80 0.75 13 one 0,055 - 0.18 0,054 3,7 1,1 0.90 fourteen one 0.1 - 0.18 0,054 3.4 1,0 0.80 fifteen one 0.12 - 0.18 0,054 2.6 0.57 0.52 16 one - 0.008 0.18 0,054 4.0 0.55 0.58 17 one - 0.01 0.18 0,054 3.8 0.82 0.75 eighteen one - 0,055 0.18 0,054 3,7 1,1 0.90 19 one - 0.1 0.18 0,054 3.3 0.7 0.80 twenty one - 0.12 0.18 0,054 3.0 0.55 0.57 prototype 1,0 0.24 0.44

Table 5 Test results of samples for strength and frost resistance depending on the flow rate of the emulsion based on OTP and the flow rate of calcium chloride solutions Component consumption kg / kg soil Humidity The strength of water-saturated samples, MPa Coefficient Note Composition number OTP based emulsion 10% calcium chloride solution 10% drainage brines soil after treatment,% on compression bending tensile frost resistance, To _mrz 7 days 7 days Soil sand (incoherent soil) one 0,07 0,021 - 7.5 2,4 0.50 0.50
Soils
5, 10
before
fabrication
samples
dried to
humidity
eleven%. 2 0.08 0.024 - 8.6 3.0 0.79 0.70 3 0.09 0,027 - 9.6 3.2 0.86 0.80 four 0.11 0,033 - 11.5 3.0 0.85 0.75 5 0.12 0,036 - 12.8 3.0 0.85 0.75 6 0,07 - 0,021 7.5 2,5 0.50 0.50 7 0.08 - 0.024 8.6 3.0 0.80 0.70 8 0.09 - 0,027 9.6 3.3 0.88 0.78 9 0.11 - 0,033 11.5 3,1 0.86 0.75 10 0.12 - 0,036 12.8 3,1 0.86 0.75 Loam soil (cohesive soil) eleven 0.11 0,033 - 11.7 3.0 0.52 0.55

Soils
composition 15,
20 before
fabrication
dried to
humidity
26% 12 0.12 0,036 - 12.8 3.2 0.90 0.80 13 0.18 0,054 - 19.2 3.8 1.15 0.9 fourteen 0.25 0,075 - 26.7 3,7 1,0 0.85 fifteen 0.26 0,078 - 27.8 3,7 1.00 0.85 16 0.11 - 0,033 11.7 2.9 0.80 0.55 17 0.12 - 0,036 12.8 3,1 0.90 0.78 eighteen 0.18 - 0,054 19.2 3,7 1,1 0.9 19 0.25 - 0,075 26.7 3,5 1,0 0.85 twenty 0.26 - 0,078 27.8 3,5 1,0 0.85

Claims (8)

1. A method of strengthening the soil, including sequential soil treatment with an aqueous solution of saponified taly pitch OTP and a 10% aqueous solution of calcium chloride, characterized in that before processing the soil, a 20% aqueous solution of OTP is mixed with used motor oil from automobile engines at t = 50-100 ° C in a ratio of 1.0: 0.01-0.1 to obtain an emulsion, the specified emulsion and a solution of calcium chloride are used in a ratio of 1: 0.28-0.3, after this treatment, the soil is kept until complete polymerization and compacted at a pressure of at least its 15.0 MPa. 2. The method according to claim 1, characterized in that as the specified solution of calcium chloride, drainage brine is used. 3. The method according to claim 1, characterized in that the soil before the specified treatment is loosened to a depth of processing. 4. The method according to claim 1, characterized in that the flow rate of the specified emulsion is 0.08-0.25 kg / kg of soil. 5. The method according to claim 4, characterized in that for said processing of incoherent soil, the flow rate of said emulsion is 0.08-0.11 kg / kg of soil. 6. The method according to claim 4, characterized in that for the indicated processing of cohesive soil, the flow rate of said emulsion is 0.12-0.25 kg / kg of soil. 7. The method according to claim 1, characterized in that for the indicated treatment of incoherent soil, the flow rate of said calcium chloride solution is 0.024-0.033 kg / kg of soil. 8. The method according to claim 1, characterized in that for the specified processing of cohesive soil, the flow rate of the specified solution of calcium chloride is 0.036-0.075 kg / kg of soil.