SU1752883A1 - Method of trenchless pipe-laying in soil - Google Patents

Description

move in the direction of the shock load, which causes the formation of a soil plug in the front of the pipe 1: The process of forming the soil plug does not begin simultaneously with the beginning of the pipe immersion, but somewhat later. At the beginning of the pipe immersion, the soil entering it through the openings, after which the impact energy is again lifted, etc. After a pipe is immersed for a given length, the impact energy is reduced until the residual displacements of the pipe cease and an intensive one begins (the process of transportation of soil remaining in it from the pipe, as the core weight decreases in

th front end, under the influence of a sign on a pipe of soil resistance to movement

alternating dynamic loads caused by the reciprocating nature of the pipe movement, loses its connectivity (the structure of the pipe breaks down and decreases, therefore the impact energy periodically decreases, preventing any significant residual displacements of the pipe and maintaining

20

thirty

35

40

Sportirovapi soil. Impacts on the pipe continue until the soil is completely removed from it.

A proportional increase in the frequency of impacts with a decrease in the impact energy makes it possible, with a constant impact mechanism power, to increase the intensity of the destruction of the soil plug and the rate of removal of soil from the pipe, i.e. improve performance

Ci and: the impact energy to stop the residual displacements after driving the pipe to the required length both bakes removing the remaining soil in it without stopping the pipe and with maximum speed.

The pipe is hammered with a shock load with the energy of an impact AMQKC is satisfactory to the expression

 . about

B ,, „p

AMCHCC 2f

QT

(one)

soil) and under the action of gravity, the maximum speed of the self-propagating forces spreads in the pipe, moving in the opposite direction of the driving block. As the volume of soil entering the pipe increases, the pressure created by this soil and preventing new portions of soil from entering the pipe increases. The formation of a ground plug 4 begins, and the tube immersion speed begins to fall.

However, up to this point, the pipe has time to move a certain distance at high speed. The time lag between the beginning of the immersion of the pipe and the beginning of the formation of a ground plug (lowering the speed of immersion) is especially significant when laying pipes of large (over 500 mm) diameter and for pipes of any diameter in loosely coupled soils.

As soon as an intensive decrease in the pipe immersion speed begins, which indicates the beginning of the formation of a soil plug, the impact energy is reduced until the residual movements of the pipe, i.e. up to

AMIN AO.TD. At the same time, the pipe 1 does not move forward, but under the action of a shock pulse and the elastic forces of the soil makes oscillatory movements with a maximum amplitude of 45

The soil core 3 is transported from pipe 1 as fast as possible. At the same time there is an intensive destruction of the soil plug. A decrease in the mass of the soil 50 in the pipe and the destruction of the soil plug reduce the resistance to movement of the pipe and it begins to move forward. At this moment, the impact energy is again increased to the value of Amaks, the process of tren ™ sporting the ground is stopped, and the pipe again begins to sink into the ground at maximum speed until the next formation of ground samples J

R

and in the event of a ground plug, the impact energy is reduced to A.

oh tr

oh tr

definable expression

(

 2C

v

Qi

R

(2)

frgde f - friction coefficient of the pipe against the ground; pipe weight;

soil core weight in the pipe; 8цг - elastic pipe failure in one

 Ular

Periodic change in the magnitude of the shock load allows an increase in the speed of immersion of the pipe and the removal of soil from it, eliminating the operation of st. improve performance The proposed method makes it possible to use a percussion mechanism with an energy of beats for immersing a pipe.

the pipes decrease, therefore the impact energy is periodically lowered, without allowing any significant residual displacements of the pipe and supporting

Sportirovapi soil. Impacts on the pipe continue until complete removal of soil from it.

A proportional increase in the frequency of impacts with a decrease in the impact energy makes it possible, at a constant impact mechanism power, to increase the intensity of destruction of the soil plug and the rate of removal of soil from the pipe, i.e. improve performance

Ci and: the development of impact energy until the termination of residual displacements after driving the pipe to the required length ensures removal of the soil remaining in it without stopping the pipe and at maximum speed.

The pipe is hammered with a shock load with the energy of an impact AMQKC satisfying expression

 . about

B ,, „p

AMCHCC 2f

QT

(one)

Your maximum speed

R

and in the event of a ground plug, the impact energy is reduced to A.

oh tr

oh tr

definable expression

(

 2C

v

Qi

R

(2)

frgde f - friction coefficient of the pipe against the ground; pipe weight;

soil core weight in the pipe; 8цг - elastic pipe failure in one

 Ular

The periodic change in the magnitude of the shock load allows an increase in the speed of immersion of the pipe and the removal of soil from it, eliminating the operation of pipe elimination, i.e. improve performance The proposed method makes it possible to use a percussion mechanism with the energy removed for immersing the pipe.

pa, considerably exceeding the sign of the impact energy, at which soil is transported from a pipe under the action of a shock load. The impact of a shock load on a pipe with high impact energy ensures that the pipe is immersed in the soil at a significant speed. This speed remains almost unchanged for a certain period of time. The soil entering the pipe at a high speed of its immersion gradually compresses. This causes a soil plug to form at the front end of the pipe and the pipe sink speed drops sharply. Reducing the impact energy to the termination of residual displacements of the pipe leads to the fact that under the action of return progressive displacements the coarse core of soil in the pipe intensively moves to the rear end of the pipe and is removed from it at maximum speed. The cores from the coarse and destruction of the soil plug provide, after increasing the impact energy to the initial value, a high speed of plunging the pipe into the ground.

Thus, both the immersion of the pipe and the removal of soil from it occurs at high speeds, exceeding the corresponding speeds using the method adopted as a prototype.

When operating in stable soils, expressions (1) and (2) allow the values to be set to which the impact energy periodically changes. The right-hand sides of expressions (1) and (2) represent the limits of the impact energy range, in which the pipe is simultaneously immersed and the soil is transported from it under the action of a shock load. when the protractor speed /

five

five

vanilla soil is zero but ground. A plug (soil compaction in the pipe) is not yet formed.

Claims (1)

Claim 1. Trenchless pipe laying method in the ground, according to which a pipe with an open front end is immersed in the soil and the soil is removed from the pipe by means of an impact load applied to the pipe, characterized in that in order to improve performance by breaking the ground plug shock load, the energy of the shock load is varied perisdially, and when the soil plug is formed, the energy of the shock load is reduced until the pipe moves forwardly and then as | the destruction of the plug increases the impact load energy to its original value. ., A method according to claim. Characterized in that the initial magnitude of the shock load energy Amaks is chosen in accordance with the expression  7f amax (QitlQjuI QTP Sljnp and when a ground plug is formed, the energy of the shock load is reduced to the value of A0-f, determined according to the expression l .of (QlE. ± QjЈlt. about A0. tr -f ZQy-Q, Vf where f is the coefficient of pipe friction about priming; QTp- pipe weight; Q to - the weight of the soil core in the pipe; elastic pipe failure za. one ud p. 3. The method according to paragraphs. 1 and 2, characterized in that by reducing the energy of the shock load, the frequency of impacts is proportionally increased. control / UGR J У747 / Г // 7J / J7 //////////// T% 7GN 7% PRG7 7, I L ..... / x -ShAP 7 / , / :. . i / 1 Fi & 1