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CN-115931669-B - Test device and test method for inhibiting soil body penetration damage by foam fluid

CN115931669BCN 115931669 BCN115931669 BCN 115931669BCN-115931669-B

Abstract

The invention discloses a foam fluid test device for inhibiting soil body infiltration damage and a test method thereof, the device comprises a main body structure, a variable water head control unit, a pore pressure monitoring unit, a computer analysis unit and a foam fluid injection unit, wherein the foam fluid injection unit comprises a liquid input module, a gas input module and a foam generator, the liquid input module and the gas input module are connected with the foam generator, the output end of the foam generator is connected with the main body structure, the test method comprises an assembling device, a sand tank is filled with sand sample by throwing, the foam fluid is injected into the sand tank for test, the water head is lifted step by step, the next water head test is carried out after infiltration flow is stabilized, the infiltration damage area change process of the top surface of the sand sample and the foam fluid occurrence range change are recorded, the pore pressure in the sand sample is monitored in real time through the pore pressure monitoring unit, and the test is stopped when the infiltration damage area is communicated with a water inlet chamber. The invention can be used for verifying and evaluating the effect of the foam fluid on inhibiting the soil body from penetrating and damaging.

Inventors

  • WANG YUAN
  • GONG JIAKUN
  • QI TIAN
  • QIU HAOTIAN

Assignees

  • 河海大学

Dates

Publication Date
20260508
Application Date
20221116

Claims (8)

  1. 1. A test method of a foam fluid soil body penetration damage inhibition test device is characterized by comprising the following steps: S1, assembling a test device, namely, casting and filling sand samples in layers in a sand tank (13), and injecting prefabricated foam fluid into the sand tank (13) to perform a penetration damage test; s2, lifting the water head of an upstream water tank (21) step by step, carrying out a next water head test after seepage is stable, recording the change process of a seepage damage area of the top surface of a sand sample and the change of the occurrence range of foam fluid, and stopping the test when the seepage damage area is communicated with a water inlet chamber (11); The test device comprises a main structure (1) for soil body penetration damage test, a variable water head control unit (2) for water inflow and drainage, a pore pressure monitoring unit (3) for monitoring the pressure of the main structure (1), a computer analysis unit (4) for analyzing the monitored pressure data, and a foam fluid injection unit (5), wherein the foam fluid injection unit (5) comprises a liquid input module (51), a gas input module (52) and a foam generator (53), the output end of the liquid input module (51) and the output end of the gas input module (52) are connected with the input end of the foam generator (53), and foam fluid generated by the foam generator (53) is injected into the main structure (1); The main structure (1) comprises a water inlet chamber (11), a water outlet chamber (12) and a sand tank (13), wherein the water inlet chamber (11) and the water outlet chamber (12) are respectively arranged at two sides of the sand tank (13), a transparent top plate (15) is arranged on the sand tank (13), a silica gel pad is further arranged between the transparent top plate (15) and the sand tank (13), a sand outlet (15.1) is arranged on one side, close to the water outlet chamber (12), of the transparent top plate (15), a foam fluid injection hole (15.2) is arranged on one side, close to the water inlet chamber (11), of the transparent top plate (15), and a pressure monitoring hole (13.1) is arranged at the front end of the sand tank (13); The water tank of the variable water head control unit (2) comprises an upstream water tank (21), a first downstream water tank (22) and a second downstream water tank (23), wherein the upstream water tank (21) is connected with a water inlet of the water inlet chamber (11), the first downstream water tank (22) is connected with a water draining hole at the top of the sand tank (16), and the second downstream water tank (23) is connected with a water outlet of the water outlet chamber (12).
  2. 2. The test method according to claim 1, wherein porous partition plates (14) for preventing sand particles from losing are arranged among the water inlet chamber (11), the water outlet chamber (12) and the sand tank (13), silica gel pads are arranged on two sides of the porous partition plates (14), and the water inlet chamber (11), the water outlet chamber (12), the sand tank (13), the porous partition plates (14) and the silica gel pads are tightly pressed and fixed through bolts and nuts.
  3. 3. The test method according to claim 2, wherein the transparent top plate (15), the sand groove (13) and the silica gel pad therebetween are fixed by pressing with bolts and nuts, a sand tank (16) for collecting sand burst generated by seepage damage is adhered at the sand outlet (15.1), a drain hole is arranged at the top of the sand tank (16), and the sand tank is connected with a water tank of the variable water head control unit (2) through a water pipe.
  4. 4. A test method according to claim 3, characterized in that the pore pressure monitoring unit (3) is provided with pore pressure sensors corresponding to the pressure monitoring holes (13.1), the sensors are connected with the pressure monitoring holes (13.1) through wires, and signals acquired by the sensors are transmitted to the computer analysis unit (4).
  5. 5. The test method according to claim 4, wherein the liquid input module (51) comprises a advection pump (51.1) and a piston container (51.2), the input end of the piston container (51.2) is connected with the advection pump (51.1), and the output end of the piston container is connected with the input end of the foam generator (53).
  6. 6. The test method according to claim 5, wherein the gas input module (52) is provided with a gas cylinder (52.1), a first pressure gauge (52.2), a pressure regulating valve (52.3), a second pressure gauge (52.4), a filter (52.5), a gas flow controller (52.6), a check valve (52.7), a back pressure valve (52.8), and a third pressure gauge (52.9) in sequence, and is connected with the input end of the foam generator (53).
  7. 7. The test method according to claim 6, wherein the S1 assembled foam fluid soil body penetration damage inhibition test device comprises the following substeps: S101, uniformly smearing vaseline on the side walls of two sides of a sand tank (13), assembling a water inlet chamber (11), a silica gel pad, a porous partition plate (14), a water outlet chamber (12) and the sand tank (13), and compacting and fixing by bolts and nuts; s102, connecting a pore pressure sensor with a pressure monitoring hole (13.1) at the front end of a sand tank (13) through a guide pipe, and connecting the pore pressure sensor with a computer analysis unit (4) through a data line; S103, preparing a test sand sample according to grain composition and compactness, performing underwater layered polishing and filling, trowelling and compacting the sand sample, sequentially placing a silica gel cushion layer and a transparent top plate (15), and fixing and screwing by using bolts; S104, opening a liquid input module (51) and a gas input module (52) to inject liquid and gas into the foam fluid generator (33) to prepare foam fluid through a advection pump (51.1) and a gas flow controller (52.6) respectively; S105, connecting the foam fluid generator (33) with a foam fluid injection hole (15.2) of the transparent top plate (15) through a conduit after the foam fluid reaches a dynamic stable state, and injecting the prefabricated foam fluid into the sand tank (13) through the foam injection hole (15.2); S106, connecting an upstream water tank (21) with a water inlet of the water inlet chamber (11), connecting a first downstream water tank (22) with a water outlet hole at the top of the sand tank (16), connecting a second downstream water tank (23) with a water outlet of the water outlet chamber (12), and opening a circulating water system of the variable water head control unit (2) to ensure that sufficient water is always reserved in the water tanks.
  8. 8. The method according to claim 7, wherein the step of performing the penetration failure test in S2 comprises the sub-steps of: S201, opening a water inlet and a sand outlet (15.1), starting a penetration damage test, lifting a water head of an upstream water tank (21) step by step, and after seepage is stable, namely measuring seepage flow for a plurality of times to be basically stable, wherein no obvious sand moves near the sand outlet (15.1) and no sand gushes out from a sand gushing pipe, so that a water head test of the next stage is carried out; S202, recording corresponding water inflow and sand inflow under each stage of water head after the test starts, recording the change process of a permeation damage area of the top surface of a sand sample and the change of the occurrence range of foam fluid, and collecting the pore pressure of a pressure monitoring hole (13.1) in real time through a pore pressure monitoring unit (3); S203, when the infiltration damage area is communicated with the water inlet chamber (11), namely a channel is formed in the top surface of a sand sample in the sand tank (13), water can enter the water inlet chamber (11) through the channel, test is stopped, data acquisition is stopped, and all valves are closed; and S204, cleaning sand samples after each group of tests are finished, drying, and resetting the test device.

Description

Test device and test method for inhibiting soil body penetration damage by foam fluid Technical Field The invention relates to a soil body infiltration damage test, in particular to a test device and a test method for inhibiting soil body infiltration damage by foam fluid. Background How to realize scientific prevention and control of permeation damage is a difficult problem to be solved in embankment engineering. The common test mode in the prior art is a variable water head penetration test, in the test process, the water head is lifted step by step, and the water inflow, the sand inflow and the pressure measuring pipe water heads at different positions are observed and recorded to obtain the penetration damage critical water head. However, the prior art cannot meet the test requirement of quantitative injection of multiphase seepage fluid into a test soil layer so as to inhibit soil body seepage damage, and the soil body pore pressure monitoring system cannot be suitable for a multiphase seepage system. Disclosure of Invention The invention aims to provide the foam fluid soil body penetration damage inhibition test device and the test method thereof, which are simple to operate and convenient to maintain, and can monitor the foam fluid to inhibit soil body penetration damage. The foam fluid restraining soil body penetration damage test device is characterized by further comprising a foam fluid injection unit, wherein the foam fluid injection unit comprises a liquid input module, a gas input module and a foam generator, the output end of the liquid input module and the output end of the gas input module are connected with the input end of the foam generator, and foam fluid generated by the foam generator is injected into the main structure. The main structure comprises a water inlet chamber, a water outlet chamber and a sand tank, wherein the water inlet chamber and the water outlet chamber are respectively arranged at two sides of the sand tank, porous partition plates for preventing sand particles from losing are arranged among the water inlet chamber, the water outlet chamber and the sand tank, silica gel pads are arranged at two sides of the porous partition plates, and the water inlet chamber, the water outlet chamber, the sand tank, the porous partition plates and the silica gel pads are fixedly pressed through bolts and nuts. Be equipped with transparent roof on the sand tank, still be equipped with the silica gel pad between transparent roof and sand tank, compress tightly fixedly through the bolt and nut, establish out the sand mouth on being close to play water chamber one side on the transparent roof, bond a sand jar that is used for collecting infiltration destruction production sand burst in sand mouth department, sand jar top is equipped with the wash port, is connected with the water tank of variable head control unit through the water pipe, is provided with foam fluid injection hole on the transparent roof in leaning on water chamber one side, the sand tank front end is provided with pressure monitoring hole. The water tank of the variable water head control unit comprises an upstream water tank, a first downstream water tank and a second downstream water tank, wherein the upstream water tank is connected with a water inlet of the water inlet chamber, the first downstream water tank is connected with a water draining hole at the top of the sand tank, and the second downstream water tank is connected with a water outlet of the water outlet chamber. The pore pressure monitoring unit is provided with a pore pressure sensor corresponding to the pressure monitoring hole, the sensor is connected with the pressure monitoring hole through a wire, and signals acquired by the sensor are transmitted to the computer analysis unit. The liquid input module comprises a advection pump and a piston container, wherein the input end of the piston container is connected with the advection pump, and the output end of the piston container is connected with the input end of the foam generator. The gas input module is sequentially provided with a gas cylinder, a first pressure gauge, a pressure regulating valve, a second pressure gauge, a filter, a gas flow controller, a one-way valve, a back pressure valve and a third pressure gauge, and is connected with the input end of the foam generator. A test method for using foam fluid to inhibit soil body penetration damage test device comprises the following steps: s1, assembling a test device, casting and filling sand samples in layers in a sand tank, and injecting prefabricated foam fluid into the sand tank to perform a penetration damage test; And S2, lifting the water head of the upstream water tank step by step, carrying out a water head test of the next stage after seepage is stable, recording the change process of the seepage damage area of the top surface of the sand sample and the change of the occurrence range of the foam fluid, and stopping the test when the