CN106198921A - A kind of subway shield construction disturbance model test device and its test method - Google Patents

Abstract

The invention discloses a subway shield construction disturbance model test device and a test method thereof. Including model tank, simulated excavation system, grouting system and monitoring system, the model tank is filled with soil, the soil body is equipped with a simulated excavation system, the grouting system is connected to the simulated excavation system, and the monitoring system is buried in the soil body of the model tank for collecting The parameters before and after the soil test disturbance; the prepared slurry is placed in the slurry storage tank, and the simulated shield shell is drawn out horizontally according to the shield speed of the simulated working condition. The middle part of the model soil is truncated, and the experimental results of the diffusion range of the grout in the soil are obtained by observing the section. The test device used in the present invention can be reused, and the synchronous grouting process under different working conditions can be repeatedly simulated at a relatively small cost. The measured data is relatively comprehensive, which provides reference for actual construction and is conducive to promoting the impact of disturbance on the surrounding soil. Research on mechanisms and principles.

Description

A kind of subway shield construction disturbance model test device and its test method

technical field

The invention relates to a subway shield construction disturbance model test device and a test method thereof, which belong to the technical field of underground construction engineering and are used for indoor simulation test research on subway shield construction disturbance.

Background technique

During the construction process of the shield method, as the shield machine continues to excavate the segments, they are also installed at the shield tail. Since the outer diameter of the segment is smaller than the outer diameter of the shield shell, gaps are constantly generated at the shield tail. Due to the poor self-stabilization ability of the soft clay around the tunnel, if the shield tail gap is not filled in time, the surrounding strata will collapse and deform. Among them, the control technology of grouting parameters such as grouting pressure and grouting volume is the key. If the grouting pressure and grouting amount are too small to meet the requirements of filling the shield tail gap, the soil around the tunnel will be actively damaged and the soil will collapse and deform; if the deformation is too large, the soil will be passively squeezed and damaged by grout. waste. Therefore, it is very important to understand the mechanism of subway shield construction disturbance.

The in-situ test has the characteristics of high detection cost, large labor input, long measurement cycle, complex site conditions, large soil heterogeneity, unstable construction parameters, etc., and the data obtained from the field test are highly discrete. Model test is an important means of scientific research, which is very helpful to the research of ground displacement related to tunnel engineering. Compared with on-site in-situ tests, model tests have the advantages of controllable density and uniformity of the model foundation, controllable boundary conditions, precise and controllable construction parameters, and real-time monitoring of responses. The model test can strictly control the influence of various irrelevant variables, and can set various test conditions at the same time. In addition, the model test cycle is short, the cost is low, and it is convenient to conduct a large number of tests and obtain a large amount of data, which is suitable for the study of the disturbance principle.

Contents of the invention

In order to solve the problems existing in the background technology, the purpose of the present invention is to provide a subway shield construction disturbance model test device and its test method, which can simulate the process of disturbance to the soil during the shield tunneling process, and can simulate different tunneling Speed and different grouting pressure and other working conditions provide a platform for the research on the disturbance mechanism of shield tunneling.

The purpose of the present invention is achieved through the following technical solutions:

One, a subway shield construction disturbance model test device:

The device includes a model tank for accommodating soil, a simulated excavation system, a grouting system and a monitoring system. The model tank is equipped with soil for simulating the construction environment of the subway shield tunnel. The soil is equipped with a simulated excavation system and grouting The system is connected to the simulation tunneling system to control the grouting, and the monitoring system is installed in the soil of the model tank to collect the parameters before and after the disturbance of the soil test.

The simulated excavation system includes a simulated shield shell and a simulated lining horizontally placed in the model groove, a model soil filled in the model groove, and a simulated shield thruster placed outside the model groove, and the simulated shield shell is made of seamless stainless steel The pipe is used as the outer pipe, and the simulated lining adopts stainless steel pipe as the inner pipe. The simulated shield shell is penetrated and installed through the side wall hole on one side of the model tank, and the simulated lining is penetrated and installed through the side wall hole on the other side of the model tank, and the simulated shield shell is installed. Outside the simulated lining, a plurality of grouting pipes are arranged axially in the gap between the simulated shield shell and the simulated lining, and the grouting pipes are arranged along the axial direction of the simulated shield shell. The thruster is connected to one end of the simulated shield shell located outside the model slot, and the simulated shield shell is pushed outward through the operation of its electric motor.

The model tank is a rectangular steel frame structure with an observation function plexiglass baffle on one side, and a circular opening is opened on the short side wall to install a simulated tunneling system.

The outer end of the grouting pipe is connected to the grouting system, the inner end of the grouting pipe extends to the edge of the simulated shield shell at the inner end of the model groove, and the simulated lining is connected to the inner wall of the simulated shield shell at the end edge of the model groove A pipe sealing ring is provided between the outer walls, and a groove for the grouting pipe to pass through is opened on the pipe sealing ring, and the inner end of the grouting pipe extends to the notch to inject grout into the shield tail space around the simulated lining.

Both the grouting pipe and the pipe sealing ring are fixed on the inner side wall of the simulated shield shell.

A flange is provided at one end of the simulated lining outside the model groove, and the simulated lining is axially limited on the side wall of the model groove by the flange.

A tank sealing ring for sealing is provided between the simulated shield shell and the side wall hole of the model tank.

The grouting system includes a grout storage tank, a flow meter, a pressure gauge, a grout pump and a main grout delivery pipe, the grout storage tank is connected to the input end of the grout pump, and the output end of the grout pump is connected to the main grout delivery pipe. The grouting pipe is connected, the grouting pump is provided with a flow meter and a pressure gauge, and a ball valve for controlling opening and closing is arranged in the main grouting pipe.

The monitoring system includes a dial gauge installed in the soil, a piezoelectric bending element, an earth pressure box, a hole pressure meter, a miniature inclinometer, a miniature cross board and a miniature penetrating probe.

Two, a subway shield construction disturbance model test method, comprising the steps:

1) Using the device, fill in the model tank as the model soil for simulating the subway shield construction environment, then compact and add water successively and leave it alone;

2) Insert the simulated shield shell and simulated lining through the model groove and bury them in the model soil, then fill in the model soil and fill it up so that both the simulated shield shell and the simulated lining are in close contact with the model soil, and continue Fill the model soil to the preset height, and embed the monitoring system when filling the soil;

3) Prepare the grout and place it in the grout storage tank of the grouting system, slowly draw out the simulated shield shell horizontally according to the simulated working condition shield speed, and inject the grout around the simulated lining through the grouting pump while pulling out the simulated shield shell;

4) Collect monitoring data through the monitoring system during the process of extracting the simulated shield shell;

5) Stop grouting after the simulated shield shell is completely pulled out of the model groove, take out the monitoring system from the model soil, take out the model soil and cut it off in the middle of the model soil along a plane perpendicular to the axial direction of the simulated shield shell. The test results of the diffusion range of the slurry in the soil are obtained by using the cross-section of the body.

The model soil is the same as the soil in the subway shield construction environment.

The preparation of the slurry is converted strictly according to the similarity ratio corresponding to the gravity of the slurry, the initial yield strength, the initial viscosity, the bleeding rate and the coagulation time, and the model slurry required by the rechecking similarity ratio is prepared by using a rotational viscometer; the main raw material of the model slurry is Lime, fly ash, medium fine sand, expansive soil, additives, water.

In the step 3), by controlling the change of the transmission gear ratio of the electric motor, the construction disturbance test under different shield tunneling speeds is realized; through the displacement control of the metering pump piston, the construction disturbance test under different grouting quantities is realized.

The beneficial effects of the present invention are:

1. The test devices used in the present invention can be used repeatedly, and the cycle of one test is about one week. Therefore, the synchronous grouting process under different working conditions can be repeatedly simulated at a small cost by controlling the difference in grouting pressure and grouting volume.

2. Multiple construction sections can be carried out in one cycle, and construction parameters such as soil pressure, pore pressure, surface settlement, shear wave velocity, inclinometer, soil density, and soil strength can be monitored in real time in each construction section, and the measurement data is relatively comprehensive , which can complete the whole process monitoring of the physical simulation of the subway shield construction disturbance.

3. On the basis of a large number of test data, systematically and detailedly study the mechanism and principle of the influence of grouting technology on the surrounding soil disturbance in subway shield construction, and explore the general law of the same grouting technology as the disturbance range and surface settlement. Then study and verify the existing grouting lifting technology, provide reference for actual construction, and propose improvement schemes.

Description of drawings

Fig. 1 is the overall structural representation of device of the present invention;

Figure 2 is a schematic diagram of the layout of the monitoring section;

Fig. 3 is a partially enlarged schematic diagram of the shield tail gap at B of this embodiment;

Fig. 4 is the partially enlarged schematic diagram of place C of this implementation example;

Fig. 5 is the partially enlarged schematic diagram of place D of this implementation example;

Figure 6 is a schematic diagram of the layout of the monitoring section of the implementation example;

In the figure: model tank 1, simulated shield shell 2, grouting pipe 3, model soil 4, simulated lining 5, slurry storage tank 6, flow meter 7, pressure gauge 8, grouting pump 9, main grout delivery pipe 10, Simulated shield thruster 11, monitoring system 12, shield tail gap 13, dial indicator 14, piezoelectric bending element 15, earth pressure box 16, hole pressure gauge 17, miniature inclinometer 18, miniature cross plate 19, miniature contactor Detect 20, pipe sealing ring 21, groove sealing ring 22.

detailed description

The present invention will be further described below in conjunction with drawings and embodiments.

As shown in Fig. 1, the present invention comprises the model groove 1 that is used to hold soil mass, simulated excavation system, grouting system and monitoring system 12, and model groove 1 is equipped with and is used for simulating the soil body of subway shield construction environment, The soil body is equipped with a simulated excavation system, the grouting system is connected to the simulated excavation system to control grouting, and the monitoring system 12 is installed in the soil body of the model tank 1 to collect test data.

The simulated excavation system includes a simulated shield shell 2 and a simulated lining 5 horizontally placed in the model tank 1, a model soil 4 filled in the model tank 1, and a simulated shield propeller 11 placed outside the model tank 1. The simulated shield shell The shield machine used to simulate the actual subway construction, the simulated shield shell 2 uses a seamless stainless steel pipe as the outer pipe, the simulated lining 5 uses a stainless steel pipe as the inner pipe, and the simulated shield shell 2 penetrates through the side wall hole on the side of the model tank 1 For installation, the simulated lining 5 is penetrated and installed through the side wall hole on the other side of the model tank 1, and the simulated shield shell 2 is set outside the simulated lining 5. After the simulated shield shell 2 and the simulated lining 5 are socketed together, as shown in Figure 2, a plurality of grouting pipes 3 are arranged at intervals along the axial direction in the gap between the simulated shield shell 2 and the simulated lining 5, and the grouting pipes 3 are arranged along the The simulated shield shell 2 is axially arranged, the grouting pipe 3 is connected to the grouting system, and the simulated shield thruster 11 is connected to the end of the simulated shield shell 2 outside the model tank 1, and the simulated shield shell 2 is driven outward by the operation of its electric motor. The simulated shield propeller can realize accurate displacement control, and can simulate different shield tunneling speeds by controlling the change of the transmission gear ratio of the electric motor.

The outer end of the grouting pipe 3 is connected to the grouting system, and the inner end of the grouting pipe 3 extends to the edge of the inner end of the simulated shield shell 2 located in the model tank 1, and to the inner side of the end edge of the simulated shield shell 2 located in the model tank 1 A pipe sealing ring 21 is provided between the wall and the outer wall of the simulated lining 5, as shown in Figure 3 and Figure 5, the pipe sealing ring 21 is provided with a groove for the grouting pipe 3 to pass through, and the inner end of the grouting pipe 3 extends to The slot injects slurry into the tail space 13 around the dummy lining 5 .

Both the grouting pipe 3 and the pipe sealing ring 21 are fixed on the inner wall of the simulated shield shell 2, and can be fixed by welding.

The end of the simulation lining 5 located outside the model tank 1 is provided with a flange, and the simulation lining 5 is axially limited on the side wall of the model tank 1 through the flange, so that the simulation lining 5 will not follow when the simulation shield shell 2 moves axially to the outer end. move.

As shown in FIG. 4 , a tank sealing ring 22 for sealing is provided between the simulation shield shell 2 and the side wall hole of the model tank 1 .

The grouting system includes a grout storage tank 6, a flow meter 7, a pressure gauge 8, a grouting pump 9 and a main grout delivery pipe 10, the grout storage tank 6 is connected with the input end of the grouting pump 9, and the output end of the grouting pump 9 is The main grouting pipe 10 is connected with the grouting pipe 3, the grouting pump 9 is provided with a flowmeter 7 and a pressure gauge 8, and the main grouting pipe 10 is provided with a ball valve for controlling opening and closing. The grouting pump 9 is a metering pump that can accurately control the amount of grouting.

As shown in Figure 6, the monitoring system 12 includes a dial indicator 14 installed in the soil for measuring soil settlement, a piezoelectric bending element 15 for measuring shear wave velocity, and an earth pressure cell for measuring earth pressure. 16. A pore piezometer 17 for measuring pore water pressure, a miniature inclinometer 18 for measuring the horizontal displacement inside the soil, a miniature cross plate 19 for measuring the shear strength of the soil, and a miniature cross plate 19 for measuring the compactness and strength The micro-penetration probe 20, the dial indicator 14, the piezoelectric bending element 15, the earth pressure box 16, the porosimeter 17, the micro-inclinometer 18, the micro-cross plate 19 and the micro-penetration probe 20 are respectively installed on the monitoring section. The dial indicator 14 is installed at the 0R, 2/3R, 4/3R, 2R, 3R from the vertical symmetry axis on the soil surface of the monitoring section; The box 16 is installed on the horizontal axis of symmetry, 2R and 3R away from the vertical axis of symmetry; the piezometer 17 is installed at 2R above, 1.5R/2R on the left, 2R/3R below, and 2.5R on the right of the simulated lining circle center; The inclinometer is an organic thin glass sheet with a width of 2cm and a thickness of 2mm, which is equal to the depth of the soil, and is affixed with strain gauges, which are respectively installed at 1.5R, 2R, and 3R from the vertical axis of symmetry; it can move. The above R is the inner diameter of the simulated lining.

The monitoring system 12 can accurately measure parameters such as deformation, pore pressure, earth pressure, stiffness, and strength of the model soil before and after disturbance, so as to realize the whole-process monitoring of physical simulation of disturbance in subway shield construction.

The concrete test process of experimental device of the present invention is as follows:

1) Fix the model tank and the driving device, fill the model tank 1 with the model soil 4 as the simulated subway shield construction environment, the model soil 4 is the same as the soil in the subway shield construction environment, and has similar moisture content and For the liquid plastic limit, fill the model soil body into the model tank 1 in 4 layers with a thickness of 10 cm, compact it layer by layer, add water, and embed each monitoring device of the monitoring system 12 when filling the soil. After the three layers are filled, the model tank The circumference of the opening on the wall is limited to fill in the soil on both sides of the lower semicircle and compact and add water;

2) Put the φ219mm simulated shield shell 2 and φ203mm simulated lining 5 through the model groove 1 and completely socket them and bury them in the model soil 4, then fill in the model soil 4 and fill it up so that the simulated shield shell 2 and the simulated lining 5 They are all in close contact with the model soil 4, continue to fill in the model soil 4 to a place 18cm away from the outer wall of the simulated shield shell, and embed each monitoring device of the monitoring system 12 during filling;

3) To prepare the slurry, put a sufficient amount of model slurry into the slurry storage tank 6. The slurry is prepared strictly according to the similarity ratio corresponding to the slurry weight, initial yield strength, initial viscosity, bleeding rate and coagulation time. Using a rotational viscometer Prepare the model slurry to check the similar ratio requirements.

The main raw materials of the concrete model slurry are lime 100kg/m ³ , fly ash 400kg/m ³ , medium and fine sand 600kg/m ³ , expansive soil 50kg/m ³ , additive 3kg/m ³ , and water 320kg/m ³ .

4) Set an appropriate gear ratio for the simulated shield propeller 11, pull the simulated shield shell 2 to move to the left at the same speed through the sliding device, and slowly draw out the simulated shield shell 2 horizontally according to the shield speed of 20cm/h in the simulated working condition to simulate In the actual subway shield machine’s progress, the simulated shield shell 2 is pulled out and the flow rate of the grouting pump 9 is controlled to meet the similarity ratio of 1:30, and the grouting pipe 3 is injected into the shield tail gap 13, the grouting pressure is 9kpa, 12kpa, and the grouting Volume 3.27cm ³ /s, 3.92cm ³ /s;

5) Collect monitoring data through the monitoring system 12 during the process of extracting the simulated shield shell 2;

In the test, on the one hand, the construction disturbance test under different shield tunneling speeds was realized by controlling the change of the transmission gear ratio of the electric motor, and on the other hand, the construction disturbance test under different grouting volumes was realized through the displacement control of the metering pump piston.

6) Stop the grouting after the simulated shield shell 2 is completely pulled out of the model groove 1, take out each monitoring device of the monitoring system 12 from the model soil body 4, and take out the model soil body 4 along a plane perpendicular to the axial direction of the simulated shield shell 2 Cut off in the middle of the model soil 4, and obtain the test results of the diffusion range of the grout in the soil by observing the cut-off surface of the soil.

This example simulates the working conditions of the U-shaped test section of Metro Line 1, and the data obtained are consistent with the in-situ shear wave velocity, inclinometer, pore pressure, and settlement data, which can better fully understand the disturbance of the subway shield construction. Process simulation and monitoring.

Claims (10)

1. A subway shield construction disturbance model test device, characterized in that: comprising a model tank (1) for accommodating soil, a simulated tunneling system, a grouting system and a monitoring system (12), a model tank (1) The soil body for simulating the construction environment of the subway shield tunnel is installed inside, the soil body is equipped with a simulated excavation system, the grouting system is connected to the simulated excavation system to control grouting, and the monitoring system (12) is installed in the soil body of the model groove (1) for The parameters before and after the soil test disturbance were collected. 2. A kind of subway shield construction disturbance model test device according to claim 1, characterized in that: the simulated tunneling system comprises a simulated shield shell (2) and a simulated lining placed horizontally in the model groove (1) (5), the model soil (4) that is filled in the model groove (1) and the simulated shield thruster (11) placed outside the model groove (1), the simulated shield shell (2) adopts seamless stainless steel pipe as The outer pipe, the simulated lining (5) adopts stainless steel pipe as the inner pipe, the simulated shield (2) is installed through the side wall hole on one side of the model tank (1), and the simulated lining (5) is installed from the other side of the model tank (1). The side wall hole on the side is penetrated and installed, the simulated shield shell (2) is sleeved outside the simulated lining (5), and a plurality of injectors are arranged at intervals along the axial direction in the gap between the simulated shield shell (2) and the simulated lining (5). The grouting pipe (3), the grouting pipe (3) is arranged axially along the simulated shield shell (2), the grouting pipe (3) is connected to the grouting system, and the simulated shield thruster (11) is connected to the simulated shield shell (2) at One end outside the model slot (1) drives the simulation shield shell (2) to push outward through the operation of its electric motor. 3. A kind of subway shield construction disturbance model test device according to claim 2, characterized in that: the outer end of the grouting pipe (3) is connected to the grouting system, and the inner end of the grouting pipe (3) extends to The simulated shield shell (2) is located at the edge of the inner end of the model slot (1), and between the inner side wall of the end edge of the simulated shield shell (2) located in the model slot (1) and the outer side wall of the simulated lining (5) A pipe sealing ring (21) is provided, and a groove for passing through the grouting pipe (3) is opened on the pipe sealing ring (21), and the inner end of the grouting pipe (3) extends to the notch to inject the slurry into the simulated lining ( 5) in the shield tail space (13) around. 4. a kind of subway shield construction disturbance model test device according to claim 2 is characterized in that: described grouting pipe (3) and pipe sealing ring (21) are all fixed on the simulated shield shell (2) medial wall. 5. a kind of subway shield construction disturbance model test device according to claim 2, is characterized in that: described simulated lining (5) is positioned at an end outside model groove (1) and is provided with flange, simulated lining (5) ) is axially limited on the side wall of the model groove (1) by the flange. 6. a kind of subway shield construction disturbance model test device according to claim 2, is characterized in that: between described simulated shield shell (2) and the side wall hole of model groove (1), be provided with and be used for sealing groove seal (22). 7. a kind of subway shield construction disturbance model test device according to claim 1, is characterized in that: described grouting system comprises grout storage tank (6), flowmeter (7), pressure gauge (8), The grouting pump (9) and the main grouting pipe (10), the grouting tank (6) is connected to the input end of the grouting pump (9), and the output end of the grouting pump (9) passes through the main grouting pipe (10) Connected with the grouting pipe (3), the grouting pump (9) is provided with a flowmeter (7) and a pressure gauge (8), and a ball valve for controlling opening and closing is arranged in the main grouting pipe (10). 8. A kind of subway shield construction disturbance model test device according to claim 1, characterized in that: said monitoring system (12) includes a dial indicator (14) installed in the soil, a piezoelectric bending element (15), earth pressure box (16), porosimeter (17), miniature inclinometer (18), miniature cross plate (19) and miniature penetrating probe (20). 9. A subway shield construction disturbance model test method is characterized in that the arbitrary described device of claim 1-8 is adopted, and the following steps are adopted: 1) Fill the model groove (1) with the model soil (4) used to simulate the construction environment of the subway shield tunneling machine, then compact it sequentially, add water and let it stand; 2) Put the simulated shield shell (2) and simulated lining (5) through the model groove (1) and completely socket them in the model soil (4), then fill in the model soil (4) and fill it up, so that Both the simulated shield shell (2) and the simulated lining (5) are in close contact with the model soil (4), and the model soil (4) is continuously filled to a preset height, and the monitoring system (12) is embedded during filling; 3) Prepare the grout and put it in the grout storage tank (6) of the grouting system, slowly draw out the simulated shield shell (2) horizontally according to the shield speed of the simulated working condition, and pass the grouting pump ( 9) Inject grout around the simulated lining (5); 4) Collect monitoring data through the monitoring system (12) during the process of extracting the simulated shield shell (2); 5) Stop grouting after the simulated shield shell (2) is completely pulled out of the model slot (1), take out the monitoring system (12) from the model soil (4), and take out the model soil (4) to be perpendicular to the simulated shield The axial plane of the shell (2) is truncated in the middle of the model soil (4), and the test results of the diffusion range of the grout in the soil are obtained by observing the sectional surface of the soil. 10. A method for a subway shield construction disturbance model test according to claim 9, characterized in that: the model soil (4) is the same as the soil in the subway shield construction environment.