CN210037042U - A friction resistance test device when a rectangular jacking pipe is jacked in - Google Patents

Abstract

The utility model discloses a friction resistance testing device when a rectangular pipe jacking is pushed in, comprising a horizontally laid simulated soil body for simulating a field soil layer; a rectangular pipe arranged on the simulated soil body for simulating the rectangular pipe jacking ; The traction device is used to provide the horizontal traction force of the rectangular pipe jacking; the dynamometer is set between the traction device and the rectangular pipe to detect the size of the traction force. The utility model can jack into the rectangular pipe by simulating actual construction conditions, thereby obtaining accurate pipe jacking friction resistance, and solves the problem that the current large-section rectangular pipe jacking construction cannot directly and accurately determine the pipe jacking friction resistance. The utility model can also test the change of the friction-reducing effect of the friction-reducing mud with time, and the adaptability between different slurries and different soil layers through multiple tests, so as to find the best combination of the friction-reducing mud suitable for the soil layer. Compare.

Description

A friction resistance test device when a rectangular jacking pipe is jacked in

technical field

The utility model relates to the technical field of pipe jacking construction, in particular to a device and method for testing frictional resistance when a rectangular pipe is jacked in.

Background technique

Pipe jacking construction is a non-excavation construction method that is increasingly developed and applied. It can cross existing roads, railways, rivers, underground pipelines, underground structures and cultural relics without excavating the surface layer. The pipe jacking construction method avoids the excavation of the urban pavement, reduces a large number of earthworks, reduces demolition and resettlement, saves construction land, reduces the disturbance of the surrounding environment and does not interrupt the ground traffic and logistics transportation activities. In recent years, the development of urban underground space, It is widely used in underground railway rail transit construction and municipal tunnel engineering.

Jacking force is a necessary parameter for pipe structure design, equipment selection and working well structure design in the pipe jacking project, and it is also the main control parameter that determines the success or failure of the project during the construction process. Usually, the resistance in the jacking process includes two parts: the head-on resistance of the cutter head and the frictional resistance of the pipeline. Under the condition that the stratum properties and the buried depth of the pipe jacking do not change much, the head-on resistance is basically stable, and the frictional resistance of the pipeline increases with the jacking. It increases with the increase of the advance distance, and plays a controlling role on the size of the jacking force. Therefore, it is an important indicator to measure the jacking efficiency and quality safety whether the pipeline friction resistance can be accurately determined.

At present, most of the determination of friction resistance in pipe jacking construction is based on theoretical calculation methods or some empirical data. The existing test device and method for testing the frictional resistance of the pipe jacking cannot simulate the actual construction conditions, and only the frictional resistance between the slurry and the pipe jacking pipe wall is tested. In fact, the friction resistance of the pipe jacking structure during the pipe jacking construction is related to the roughness of the contact interface, the properties of the soil, the properties of the slurry and many other factors, especially the effect of the interaction between the slurry and the soil on the friction resistance. Therefore, ignoring the influence of soil, only testing the frictional resistance between the jacking pipe and the slurry will be quite different from the actual situation. In addition, the existing test device is complicated and cannot simulate the jacking process of the pipe. Therefore, in order to reasonably determine the friction resistance of the pipe jacking structure during the pipe jacking construction, a device and method that can directly and accurately measure the friction resistance between the structure and the soil during the pipe jacking process are urgently needed.

Utility model content

The purpose of the utility model is to provide a friction resistance testing device and method for the rectangular pipe jacking, which can simulate the actual construction conditions to jack into the rectangular pipe, so as to obtain the exact size of the pipe jacking friction resistance, and solve the problem of the current large-section rectangular pipe. The problem that the friction resistance of the pipe jacking cannot be directly and accurately determined in the pipe jacking construction.

In order to achieve the above purpose, the technical scheme of the present utility model is: a friction resistance test device when a rectangular jacking pipe is jacked, comprising:

Horizontally laid simulated soil for simulating field soil layers;

A rectangular tube set on the simulated soil to simulate a rectangular jacking tube;

Traction device, used to provide horizontal traction for rectangular pipe jacking;

The dynamometer is arranged between the traction device and the rectangular tube to detect the size of the traction force.

Further, it also includes a test bench, the test bench is provided with a rectangular groove, and the simulated soil is laid in the rectangular groove.

Further, the rectangular tube is a rectangular hollow box with built-in weights, the bottom of the rectangular tube jacking end is provided with a chamfer, and the two sides of the rectangular tube jacking end are respectively provided with a number of positioning holes corresponding to different heights of the center of gravity of the rectangular tube, corresponding to A traction rope is connected between the positioning holes, and the middle part of the traction rope is connected with the fixed end of the dynamometer.

Further, the traction device is arranged at one end of the simulated soil, including a motor and a frequency converter for controlling the speed of the motor, a soft wire rope is wound on the rotating shaft of the motor, and the end of the soft wire rope is connected with the tensile end of the dynamometer, During the test, the soft steel wire rope is reeled by the rotating shaft of the rotating motor, the soft steel wire rope stretches the dynamometer, and the horizontal displacement of the rectangular pipe is driven by the dynamometer and the traction rope, simulating the jacking process of the rectangular pipe.

Further, the frequency converter is also connected with a computer, which is used to control the control frequency output by the frequency converter and realize the speed control of the motor; the computer is also connected with the dynamometer to collect the force value measured by the dynamometer. .

Further, the dynamometer adopts an electronic spring dynamometer.

A test method for a friction resistance test device when a rectangular jacking pipe is jacked in, comprising the following steps:

(1) Simulate the weight of soil covering on the rectangular jacking pipe during the actual jacking process by increasing or decreasing the weight in the rectangular pipe;

(2) Adjust the installation height of the traction rope according to the center of gravity of the rectangular tube obtained in step (1);

(3) Put the rectangular tube obtained in step (2) into the rectangular groove of the test bench, connect the soft wire rope to the middle of the traction rope, adjust the height of the rectangular tube to make the soft wire rope in a horizontal state, then determine the lower surface of the rectangular tube is the simulated soil pavement depth;

(4) According to the paving depth obtained in step (3), fill the simulated soil into the rectangular groove on the test bench in layers according to the soil layer conditions of the construction site;

(5) Place the rectangular tube obtained in step (2) on the paved simulated soil, connect the fixed end of the electronic spring dynamometer to the middle of the traction rope, and connect the tensile end of the electronic spring dynamometer to the Soft wire rope connection;

(6) Control the output frequency of the inverter through the computer, adjust the speed of the motor, turn on the motor, and make the rectangular tube travel at a constant speed. The force value measured by the dynamometer collected by the computer is the friction resistance.

The beneficial effects of the utility model are: the utility model can jack into the rectangular pipe by simulating actual construction conditions, so as to obtain accurate pipe jacking friction resistance, and solve the problem that the current large-section rectangular pipe jacking construction cannot directly and accurately determine the pipe jacking friction resistance size issue. In addition, the utility model can also test the change of the friction-reducing effect of the friction-reducing mud with time, and the adaptability between different slurries and different soil layers through multiple tests, so as to find the best friction-reducing effect suitable for the soil layer. Mud mix ratio.

Description of drawings

Fig. 1 is the structural representation of the utility model;

Figure 2 is a schematic structural diagram of a rectangular tube.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

As shown in Figure 1, a friction resistance test device when a rectangular jacking pipe is jacked, including:

Horizontally laid simulated soil body 1, used to simulate the soil layer on site;

Test bench 2, a rectangular groove 3 is provided on the test bench 2, and the simulated soil body 1 is laid in the rectangular groove 3;

The rectangular pipe 4 arranged on the simulated soil body 1 is used to simulate the rectangular jacking pipe;

The traction device 5 is used to provide the horizontal traction force for the rectangular pipe 4 to be pushed forward;

The dynamometer 6 is arranged between the traction device 5 and the rectangular tube 4, and is used for detecting the magnitude of the traction force; the dynamometer 6 adopts an electronic spring dynamometer.

The rectangular tube 4 is a rectangular hollow box with built-in weights. As shown in FIG. 2 , a chamfer 41 is provided at the lower part of the jacking end of the rectangular tube 4 , and a plurality of corresponding rectangular tubes 4 are respectively arranged on both sides of the jacking end of the rectangular tube 4 . The positioning holes 42 with different heights of the center of gravity are connected with a traction rope 43 between the corresponding positioning holes 42 , and the middle part of the traction rope 43 is connected with the fixed end of the dynamometer 6 .

The traction device 5 is arranged at one end of the simulated soil 1, and includes a motor 51 and a frequency converter 52 that controls the rotational speed of the motor 51. A soft wire rope 53 is wound on the rotating shaft of the motor 51, and the end of the soft wire rope 53 is connected to the dynamometer 6. During the test, the soft wire rope 53 is reeled by the rotating shaft of the rotating motor 51, the soft wire rope 53 stretches the dynamometer 6, and drives the horizontal displacement of the rectangular tube 4 through the dynamometer 6 and the traction rope 43, simulating The jacking process of the rectangular jacking pipe.

The frequency converter 52 is also connected with a computer 54 for controlling the control frequency output by the frequency converter 52 to realize the speed control of the motor 51; the computer 54 is also connected with the dynamometer 6 for collecting the measured strength value.

The above-mentioned device can simulate the actual construction conditions to jack into the rectangular pipe, so as to obtain the accurate pipe jacking friction resistance, and solve the problem that the current large-section rectangular pipe jacking construction cannot directly and accurately determine the pipe jacking friction resistance. The specific use process is:

A test method for a friction resistance test device when a rectangular jacking pipe is jacked in, comprising the following steps:

(1) By increasing or decreasing the weight in the rectangular pipe 4, simulate the weight of the soil covering on the rectangular jacking pipe during the actual jacking process;

(2) Adjust the installation height of the traction rope 43 according to the center of gravity of the rectangular tube 4 obtained in step (1);

(3) Put the rectangular tube 4 obtained in step (2) into the rectangular groove 3 of the test bench 2, connect the soft wire rope 53 to the middle of the traction rope 43, adjust the height of the rectangular tube 4, and make the soft wire rope 53 in a horizontal state , then it is determined that the lower surface of the rectangular pipe 4 is the paving depth of the simulated soil body 1;

(4) According to the paving depth obtained in step (3), fill the simulated soil body 1 into the rectangular groove 3 on the test bench in layers according to the soil layer conditions of the construction site;

(5) Place the rectangular tube 4 obtained in step (2) on the paved simulated soil 1, connect the fixed end of the electronic spring dynamometer to the middle of the traction rope 43, and pull the The extension end is connected with the soft wire rope 53;

(6) Control the frequency converter 52 to output the control frequency through the computer 54, adjust the speed of the motor 51, turn on the motor 51, and make the rectangular tube 4 travel at a constant speed. The force value measured by the dynamometer 6 collected by the computer 54 is the frictional resistance. .

In the above test process, multiple sets of tests can be carried out by adding or reducing weights to simulate the influence of the soil weight on the friction resistance of different jacking pipes in the actual project.

On the basis of the above test, by laying a layer of anti-friction mud on the surface of the simulated soil, the friction resistance under grouting conditions and the change of the anti-friction effect of the anti-friction mud with time can also be tested. In addition, the friction-reducing effect of different slurries can also be tested by tiling the anti-friction slurries with different mix ratios on the simulated soil.

The described embodiments are only some, but not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative work shall fall within the scope of the present invention.

Claims (6)

1. A frictional resistance testing device for jacking a rectangular jacking pipe is characterized by comprising

The simulation soil body is horizontally laid and used for simulating a field soil layer;

the rectangular pipe is arranged on the simulated soil body and used for simulating a rectangular top pipe;

the traction device is used for providing horizontal traction force for jacking the rectangular pipe;

and the dynamometer is arranged between the traction device and the rectangular pipe and is used for detecting the traction force.

2. The apparatus for testing the frictional resistance during jacking of a rectangular jacking pipe as claimed in claim 1, further comprising a test bed, wherein the test bed is provided with a rectangular groove, and the simulated soil body is laid in the rectangular groove.

3. The apparatus according to claim 1, wherein the rectangular tube is a rectangular hollow box with weights inside, a chamfer is provided at the lower part of the pushing end of the rectangular tube, a plurality of positioning holes corresponding to different heights of the center of gravity of the rectangular tube are respectively provided at both sides of the pushing end of the rectangular tube, a pulling rope is connected between the corresponding positioning holes, and the middle part of the pulling rope is connected with the fixed end of the dynamometer.

4. The apparatus according to claim 3, wherein the traction device is disposed at one end of the simulated soil body, and comprises a motor and a frequency converter for controlling the rotation speed of the motor, a flexible steel wire rope is wound around a rotating shaft of the motor, the end of the flexible steel wire rope is connected with a stretching end of the dynamometer, during the test, the flexible steel wire rope is wound by rotating the rotating shaft of the motor, the dynamometer is stretched by the flexible steel wire rope, and the dynamometer and the traction rope drive the rectangular pipe to move horizontally, so as to simulate the jacking process of the rectangular pipe.

5. The friction resistance testing device during jacking of the rectangular jacking pipe as claimed in claim 4, wherein the frequency converter is further connected with a computer for controlling the control frequency output by the frequency converter to realize the rotation speed control of the motor; the computer is also connected with the dynamometer and is used for collecting the force value measured by the dynamometer.

6. The apparatus for testing the frictional resistance during the jacking of a rectangular pipe as claimed in claim 1, wherein said load cell is an electronic spring load cell.

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