A soil collapse test device and test method

Abstract

The present invention discloses a test device and test method for soil disintegration, and the test device includes a disintegration system, a water injection system, a pressurization system and a controller. The disintegration system includes a glass water tank, a disintegration box and a tensiometer; the glass water tank is fixed on a support base and the top is connected to a cover plate through a lifting mechanism; the disintegration box contains a test soil sample and includes a box frame and four box side walls; the box frame includes a box bottom plate, a box top plate and four box support columns; the box bottom plate includes a bottom plate center, front, rear, left and right bottom plate edges; the four box side walls are arranged one by one between the front bottom and the top plate edge, the rear bottom and the top plate edge, the left bottom and the top plate edge, and the right bottom and the top plate edge; the disintegration box is arranged in the middle of the glass water tank; the tensiometer is installed in the middle of a hollow rod fixed to the top of the disintegration box. The test device and test method of the present invention can realize the disintegration test of soil samples with different immersion surfaces under specific water pressure.

Description

Technical Field

[0001] The invention relates to a test device and a test method for soil collapse. Background Art

[0002] Disintegration refers to the phenomenon that rock and soil are broken and disintegrated under the infiltration of water. Special rock and soil bodies widely distributed in my country, such as loess, red sandstone, carbonaceous mudstone, granite residual soil, etc., are prone to disintegration when exposed to water. The structural disintegration and cracking of disintegrating rock and soil bodies after absorbing water will not only cause geological disasters such as soil erosion and landslides, but also cause great troubles for projects such as road construction, foundation treatment, and drilling excavation. Therefore, accurate evaluation of the disintegration of rock and soil bodies and determination of the disintegration speed and amount of rock and soil bodies under different water pressure conditions and immersion surface conditions have important theoretical basis and application value for the construction of underground projects under water-rich conditions.

[0003] At present, the research method for the disintegration of rock and soil in the laboratory is to place the test device containing the soil sample into a water tank filled with pure water, measure the disintegration amount by mass method or volume method, and then calculate the disintegration rate and disintegration resistance coefficient. However, the disintegration test devices in the existing methods and specifications cannot consider the influence of immersion pressure. However, whether in nature or in engineering practice, the water body in contact with the soil has a certain hydrostatic pressure, and the change in water pressure has a significant effect on the disintegration rate and disintegration amount of the soil that cannot be ignored. At the same time, not all engineering backgrounds have soil that is completely immersed in water. For example, after drilling and excavation of marine pile foundations, only one side of the hole wall soil is immersed in water. Therefore, the research and development of soil disintegration devices that can consider immersion pressure and can achieve immersion on different sides is of great importance for the study of soil disintegration under different engineering backgrounds, and has significant guiding significance for the construction of underground projects. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the prior art and provide a soil disintegration test device and test method, which can realize soil disintegration tests under different water pressures and different immersion surfaces, and can effectively guide rock and soil construction operations under water-rich conditions.

[0005] A technical solution to achieve the purpose of the present invention is: a soil disintegration test device, including a disintegration system, a water injection system, a pressurization system and a controller; wherein,

[0006] The disintegration system comprises a support, a glass water tank, a disintegration box and a tensiometer;

[0007] The bracket includes a bracket bottom plate, a bracket base fixed to the center of the bracket bottom plate, four bracket columns fixed to the four corners of the bracket bottom plate, and a bracket top plate fixed to the tops of the four bracket columns;

[0008] The glass water tank is fixed on the support base, a water inlet and a pressurized water inlet are provided on the bottom plate of the glass water tank, and a cover plate is connected to the top of the glass water tank through a lifting mechanism;

[0009] The disintegration box contains a soil sample and includes a box frame and four box side walls; wherein,

[0010] The box frame includes a box bottom plate, a box top plate and four box support columns; the box bottom plate includes a bottom plate center, a front bottom plate edge, a rear bottom plate edge, a left bottom plate edge and a right bottom plate edge; the bottom plate center is a rectangular box-shaped structure and includes a panel, a receiving plate and front, rear, left and right side plates connected one by one between the front, rear, left and right sides of the panel and the receiving plate; an upper slot is correspondingly provided at the upper part of the front and rear side plates; a lower slot is correspondingly provided at the lower part of the left and right side plates; the front bottom plate edge and the rear bottom plate edge are moved forward and backward by a mechanism The upper part of the front side plate and the upper part of the rear side plate are connected one by one to the left bottom plate edge and the right bottom plate edge through a left-right moving mechanism; the box top plate includes a top plate center part and a front top plate edge, a rear top plate edge, a left top plate edge and a right top plate edge fixedly connected to the front, rear, left and right sides of the top plate center part one by one, and a hollow rod is vertically connected to the center of the top surface of the top plate center part; four box support columns are connected one by one between the four corners outside the bottom plate center part and the four corners outside the top plate center part;

[0011] Four box side walls are arranged one by one between the edge of the front bottom plate and the edge of the front top plate, between the edge of the rear bottom plate and the edge of the rear top plate, between the edge of the left bottom plate and the edge of the left top plate, and between the edge of the right bottom plate and the edge of the right top plate;

[0012] The disintegration box is arranged in the middle of the glass water tank, and the upper end of the hollow rod passes through the cover plate of the glass water tank;

[0013] The tension gauge is installed in the middle of the hollow rod, and the signal line of the tension gauge is passed through the hollow rod;

[0014] The water injection system includes a water tank, an air inlet valve arranged at the top of the water tank, and a water outlet valve arranged at the bottom of the water tank; the inlet of the air inlet valve is connected to the air compressor; the outlet of the water outlet valve is connected to the water inlet of the glass water tank through a water inlet pipe;

[0015] The pressurizing system is connected to the pressurizing air inlet of the glass water tank through a pressurizing water inlet pipe;

[0016] The controller is respectively connected to the dynamometer, the front-rear moving mechanism, the left-right moving mechanism and the pressurizing system by signals.

[0017] The above-mentioned soil collapse test device, wherein the lifting mechanism includes two lifting ears, two pairs of fixed pulleys, two upright cylinders, two groups of weights and two steel cables; the two lifting ears are symmetrically fixed on the top surface of the cover plate of the glass water tank, one on the left and one on the right; the two pairs of fixed pulleys are fixed one-to-one on the bottom surface of the bracket top plate and are located one-to-one above the two lifting ears; the two upright cylinders are fixed one-to-one on the bracket bottom plates on the left and right sides of the glass water tank; the two groups of weights are arranged one-to-one in the two upright cylinders; one end of the two steel cables is connected to the top of the two groups of weights one-to-one, and the other ends of the two steel cables are connected to the two lifting ears after passing through the two pairs of fixed pulleys one-to-one.

[0018] The above-mentioned soil disintegration test device, wherein the front-to-back moving mechanism includes a pair of front-to-back sliding rails, a pair of front sliders and a pair of rear sliders; the pair of front-to-back sliding rails are fixed one-to-one to the upper part of the left plate and the upper part of the right plate; the pair of front sliders are installed one-to-one to the front part of the pair of front-to-back sliding rails, the pair of front sliders are respectively connected one-to-one to the rear end faces of the two ends of the edge of the front bottom plate through a pull rod, and the two ends of the edge of the front bottom plate are respectively slidably installed on the pair of front-to-back sliding rails; the pair of rear sliders are installed one-to-one to the rear part of the pair of front-to-back sliding rails, the pair of rear sliders are respectively connected one-to-one to the front end faces of the two ends of the edge of the rear bottom plate through a pull rod, and the two ends of the edge of the rear bottom plate are respectively slidably installed on the pair of front-to-back sliding rails;

[0019] The left-right moving mechanism comprises a pair of left-right sliding rails, a pair of left sliders and a pair of rear sliders; the pair of left-right sliding rails are fixed one-to-one to the lower part of the front side plate and the lower part of the rear side plate; a pair of left sliders are installed one-to-one to the left part of the pair of left-right sliding rails, the pair of left sliders are respectively connected one-to-one to the right end faces of the two ends of the edge of the left bottom plate through a pull rod, and the two ends of the edge of the left bottom plate are respectively slidably installed on the pair of left-right sliding rails; a pair of right sliders are installed one-to-one to the right side of the pair of left-right sliding rails, the pair of right sliders are respectively connected one-to-one to the left end faces of the two ends of the edge of the right bottom plate through a pull rod, and the two ends of the edge of the right bottom plate are respectively slidably installed on the pair of left-right sliding rails;

[0020] The front slider, the rear slider, the left slider and the rear slider are all electrically controlled sliders.

[0021] In the above-mentioned soil collapse test device, the water injection system also includes a steel frame for installing the water tank.

[0022] Another technical solution for achieving the purpose of the present invention is: a test method for soil collapse, based on the above-mentioned test device for soil collapse, the test method comprises the following steps:

[0023] Step S1, cutting the soil sample according to the shape of the disintegration box and measuring the parameters of the soil sample; the parameters of the soil include the mass m of the soil before disintegration and the natural density ρ of the soil s ;

[0024] Step S2, firstly, the cover plate of the glass water tank is raised by adding the weight of two sets of weights, then the soil sample is placed in the box frame of the disintegration box, and then the four box side walls of the disintegration box are arranged one by one between the edge of the front bottom plate and the edge of the front top plate, between the edge of the rear bottom plate and the edge of the rear top plate, between the edge of the left bottom plate and the edge of the left top plate, and between the edge of the right bottom plate and the edge of the right top plate, so that the disintegration box remains airtight, and then the cover plate of the glass water tank is pulled down by reducing the weight of the two sets of weights, so that the glass water tank is sealed;

[0025] Step S3, connecting the air compressor to the air inlet valve of the water injection system, setting the pressure, opening the water outlet valve to inject water into the glass water tank of the disintegration system until the glass water tank is full, and closing the air compressor and the water outlet valve;

[0026] Step S4: applying pressure to the water in the glass water tank through a pressurizing system;

[0027] Step S5, after the water pressure in the glass water tank reaches the target value and stabilizes, the control program built into the controller is turned on, and the front bottom plate edge, the rear bottom plate edge, the left bottom plate edge, and the right bottom plate edge are retracted to the center of the bottom plate one by one by controlling a pair of front sliders and / or a pair of rear sliders and / or a pair of left sliders and / or a pair of right sliders in the disintegration box, so that one box side wall and / or two box side walls and / or three box side walls and / or four box side walls fall naturally into the water, thereby simulating the condition of the soil sample being immersed in water on one side and / or two sides and / or three sides and / or four sides, and starting to record the indication value T of the tensiometer;

[0028] Step S6, observing the reading of the tensiometer, if the reading of the tensiometer does not change or changes by no more than 0.01N for two consecutive hours, it is considered that the soil sample has completely disintegrated;

[0029] Step S7, calculating the mass and disintegration rate of the disintegrated soil;

[0030] The mass m1 of the collapsed soil is calculated according to the following formula (1):

[0031]

[0032] In formula (1), m is the mass of the soil before collapse; T is the reading of the tensiometer; ρ w is the density of water, ρ at room temperature w =1.0×103kg / m 3 ρs is the natural density of the soil;

[0033] According to the following formula (2), soil disintegration rate v:

[0034]

[0035] In formula (2), t is the time interval set for recording the reading of the dynamometer.

[0036] In the above-mentioned test method for soil collapse, when performing step S1, the mass m of the soil before collapse is measured by a mechanical balance with an accuracy of 0.001 g; the natural density ρ of the soil s Measured by the ring knife method.

[0037] In the above-mentioned test method for soil collapse, when performing step S7, formula (1) is obtained based on the mass m of the soil before collapse = the mass m1 of the collapsed soil + the mass m2 of the uncollapsed soil, and the force exerted on the uncollapsed soil in water is expressed by the following formula:

[0038]

[0039] In the above formula, F 浮 It is the buoyancy of uncollapsed soil in water.

[0040] The soil disintegration test device and test method of the present invention have the following characteristics:

[0041] (1) The present invention applies a specific pressure to the water around the soil body through a pressurizing system, and can realize the disintegration test of the tested soil body under a specific water pressure;

[0042] (2) The present invention controls the shrinkage of the edges around the bottom plate of the disintegration box to allow the side walls of the box to fall naturally, thereby flexibly controlling the number of submerged surfaces of the soil sample and realizing soil disintegration tests under different water pressures and different numbers of submerged surfaces, thereby realizing the disintegration of the soil under conditions where one or more sides are submerged in water, accurately simulating the amount and speed of soil disintegration under different engineering backgrounds, and having significant guiding significance for the construction of underground projects under water-rich conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic structural diagram of a soil disintegration test device of the present invention;

[0044] Figure 2 It is a schematic structural diagram of a disintegration system in a soil disintegration test device of the present invention;

[0045] Figure 3 is a perspective view of a cover plate of a glass water tank of the present invention;

[0046] Figure 4 is a perspective view of a disintegration box of the present invention;

[0047] Figure 5 is a perspective view of the disintegration box of the present invention with the side wall of the box separated from the box frame;

[0048] Figure 6 is a perspective view of a box frame of a disintegration box of the present invention;

[0049] Figure 7 is a perspective view of a box bottom plate of the disintegration box of the present invention;

[0050] Figure 8 is a perspective view of the interior of the bottom plate of the disintegration box of the present invention;

[0051] Fig. 9 It is a partial perspective view of the left-right moving mechanism in the disintegration box of the present invention. DETAILED DESCRIPTION

[0052] The present invention will be further described below in conjunction with the accompanying drawings.

[0053] See also Figures 1 to 9 The soil disintegration test device of the present invention comprises a disintegration system, a water injection system, a pressurization system and a controller.

[0054] The disintegration system is used to disintegrate the soil under specific water pressure and specific water surface conditions, and simultaneously obtain the disintegration amount and disintegration rate of the soil. The disintegration system includes a bracket, a glass water tank 2, a disintegration box 3 and a tensiometer 4.

[0055] The bracket is used to support the glass water tank 2; the bracket includes a bracket bottom plate 11, a bracket base 12 fixed to the center of the bracket bottom plate 11, four bracket columns 13 fixed to the four corners of the bracket bottom plate 11, and a bracket top plate 14 fixed to the tops of the four bracket columns 13;

[0056] The glass water tank 2 is fixed on the bracket base 12. A water inlet and a pressurized water inlet are provided on the bottom plate of the glass water tank 2. A water inlet valve 2A is installed in the water inlet, and a pressurized water inlet valve 2B is installed in the pressurized water inlet. The top of the glass water tank 2 is connected to a cover plate 20 through a lifting mechanism.

[0057] The lifting mechanism is used to disassemble and install the cover plate 20; the lifting mechanism includes two lifting ears 21, two pairs of fixed pulleys 22, two upright cylinders 23, two groups of weights 24 and two steel cables 25; wherein, the two lifting ears 21 are symmetrically fixed on the top surface of the cover plate 20 of the glass water tank 2, one on the left and one on the right; the two pairs of fixed pulleys 22 are fixed one by one on the bottom surface of the bracket top plate 14 and are located one by one above the two lifting ears 21; the two upright cylinders 23 are fixed one by one on the bracket bottom plates 11 on the left and right sides of the glass water tank 2; the two groups of weights 24 are arranged one by one in the two upright cylinders 23; one end of the two steel cables 25 is connected to the top of the two groups of weights 24 one by one, and the other ends of the two steel cables 25 are connected to the two lifting ears 21 after passing through the two pairs of fixed pulleys 22 one by one.

[0058] The disintegration box 3 contains a test soil sample 10 and comprises a box frame 3A and four box side walls 3B.

[0059] The box frame 3A includes a box bottom plate 31, a box top plate 32 and four box support columns 33; wherein,

[0060] The box bottom plate 31 includes a bottom plate center portion 310, a front bottom plate edge 311, a rear bottom plate edge 312, a left bottom plate edge 313 and a right bottom plate edge 314; the front bottom plate edge 311, the rear bottom plate edge 312, the left bottom plate edge 313 and the right bottom plate edge 314 are used to receive four box side walls 3B in a one-to-one correspondence; the bottom plate center portion 310 is a rectangular box-shaped structure and includes a panel 310a, a receiving plate 310b and a front side plate 3101, a rear side plate 3102 connected between the front, rear, left and right sides of the panel 310a and the receiving plate 310b in a one-to-one correspondence. 02, left side plate 3103 and right side plate 3104; an upper slot is correspondingly provided at the upper part of the front side plate 3101 and the rear side plate 3102; a lower slot is correspondingly provided at the lower part of the left side plate 3103 and the right side plate 3104; the front bottom plate edge 311 and the rear bottom plate edge 312 are connected to the upper part of the front side plate 3101 and the upper part of the rear side plate 3102 one by one through a front-to-back moving mechanism, and the left bottom plate edge 313 and the right bottom plate edge 314 are connected to the lower part of the left side plate 3103 and the lower part of the right side plate 3104 one by one through a left-to-right moving mechanism;

[0061] The front-to-back movement mechanism includes a pair of front-to-back sliding rails 341, a pair of front sliders 342 and a pair of rear sliders 343; wherein the pair of front-to-back sliding rails 341 are fixed one-to-one to the upper part of the left side plate 3103 and the upper part of the right side plate 3104; the pair of front sliders 342 are installed one-to-one to the front part of the pair of front-to-back sliding rails 341, and the pair of front sliders 342 are respectively connected to the rear end surfaces of the two ends of the front bottom plate edge 311 through a pull rod, and the two ends of the front bottom plate edge 311 are respectively slidably installed on the pair of front-to-back sliding rails 341; the pair of rear sliders 343 are installed one-to-one to the rear part of the pair of front-to-back sliding rails 341, and the pair of rear sliders 343 are respectively connected to the front end surfaces of the two ends of the rear bottom plate edge 312 through a pull rod, and the two ends of the rear bottom plate edge 312 are respectively slidably installed on the pair of front-to-back sliding rails 341;

[0062] The left-right moving mechanism includes a pair of left-right sliding rails, a pair of left sliders and a pair of rear sliders; wherein the pair of left-right sliding rails are fixed to the lower part of the front side plate 3101 and the lower part of the rear side plate 3102 in a one-to-one correspondence; a pair of left sliders are installed to the left part of the pair of left-right sliding rails in a one-to-one correspondence, and the pair of left sliders are respectively connected to the right end faces of the two ends of the left bottom plate edge 313 in a one-to-one correspondence through a pull rod, and the two ends of the left bottom plate edge 313 are respectively slidably installed on the pair of left-right sliding rails; a pair of right sliders are installed to the right side of the pair of left-right sliding rails in a one-to-one correspondence, and the pair of right sliders are respectively connected to the left end faces of the two ends of the right bottom plate edge 314 in a one-to-one correspondence through a pull rod, and the two ends of the right bottom plate edge 314 are respectively slidably installed on the pair of left-right sliding rails;

[0063] The front slider 342 , the rear slider 343 , the left slider 352 and the rear slider are all electrically controlled sliders.

[0064] The top plate 32 of the box body includes a top plate center portion and front top plate edges, rear top plate edges, left top plate edges and right top plate edges fixedly connected to the front, rear, left and right sides of the top plate center portion one by one, and a hollow rod 30 is vertically connected to the center of the top surface of the top plate center portion;

[0065] Four box support columns 33 are connected one by one between the four corners outside the center part 310 of the bottom plate and the four corners outside the center part of the top plate;

[0066] The four box side walls 3B are arranged one by one between the front bottom plate edge 311 and the front top plate edge, between the rear bottom plate edge 312 and the rear top plate edge, between the left bottom plate edge 313 and the left top plate edge, and between the right bottom plate edge 314 and the right top plate edge;

[0067] The dimensions of the front and rear box side walls of the four box side walls 3B are length×width×height=8cm×1cm×17cm, the dimensions of the left and right box side walls are length×width×height=8cm×1cm×19cm, the plane dimensions of the bottom plate center 310 are length×width=8cm×8cm, the heights of the front side plate 3101, the rear side plate 3102, the left side plate 3103 and the right side plate 3104 are all 4cm; the dimensions of the front bottom plate edge 311, the rear bottom plate edge 312, the left bottom plate edge 313 and the right bottom plate edge 314 are all length×width×height=8cm×1cm×1cm;

[0068] The front bottom plate edge 311 and the rear bottom plate edge 312 may also be connected to the lower part of the front side plate 3101 and the lower part of the rear side plate 3102 in a one-to-one correspondence, and the left bottom plate edge 313 and the right bottom plate edge 314 may be connected to the upper part of the left side plate 3103 and the upper part of the right side plate 3104 in a one-to-one correspondence;

[0069] The disintegration box 3 is arranged in the middle of the glass water tank 2, and the upper end of the hollow rod 30 passes through the cover plate 20 of the glass water tank 2;

[0070] The tension gauge 4 is installed in the middle of the hollow rod 30 , and a signal line 40 of the tension gauge 4 is passed through the hollow rod 30 .

[0071] The water filling system is used to fill water into the glass water tank 2; the water filling system includes a water tank 5, an air inlet valve 51 arranged on the top of the water tank 5 and a water outlet valve 52 arranged at the bottom of the water tank 5; the water tank 5 is installed on a steel frame 50; the inlet of the air inlet valve 51 is connected to an external air compressor; the outlet of the water outlet valve 52 is connected to the water inlet of the glass water tank 2 through a water inlet pipe.

[0072] The pressurizing system 6 is a pressure and volume controller, which is used to apply a specific water pressure to the glass water tank 2 after water is filled; the pressurizing system 6 is connected to the pressurizing water inlet valve 2B of the pressurizing water inlet at the bottom of the glass water tank 2 through a pressurizing water inlet pipe. After the pressurizing water inlet valve 2B is opened, different pressures are applied to the water in the glass water tank 2 of the disintegration system by controlling the water pressure.

[0073] The controller 7 is respectively connected to the dynamometer 4 , the front slider 342 and the rear slider 343 of the front-rear moving mechanism, the left slider 352 and the rear slider 353 of the left-right moving mechanism, and the pressurizing system 6 by signals.

[0074] The soil disintegration test method of the present invention is based on the soil disintegration test device of the present invention, and the test method comprises the following steps:

[0075] Step S1, cutting the soil sample 10 using a soil cutting mold according to the shape of the disintegration box, and measuring the parameters of the soil; the parameters of the soil include the mass m of the soil before disintegration and the natural density ρ of the soil s; The mass m of the soil before collapse is measured by a mechanical balance with an accuracy of 0.001g; the natural density ρ of the soil s The ring knife method was used for determination;

[0076] Step S2, firstly, the cover plate 20 of the glass water tank 2 is raised by increasing the weight of the two sets of weights 24, then the soil sample 10 is placed in the box frame 3A of the disintegration box 3, and then the four box side walls 3B of the disintegration box 3 are arranged one by one between the front bottom plate edge 311 and the front top plate edge, between the rear bottom plate edge 312 and the rear top plate edge, between the left bottom plate edge 313 and the left top plate edge, and between the right bottom plate edge 314 and the right top plate edge, so that the disintegration box 3 remains airtight, and then the cover plate 20 of the glass water tank 2 is pulled down by reducing the weight of the two sets of weights 24, and the cover plate 20 is connected to the side wall of the glass water tank 2 by bolts to make the glass water tank 2 sealed;

[0077] Step S3, connect the external air compressor to the air inlet valve 51 of the water injection system, and set the pressure to be controlled at 20-50 kPa; open the water outlet valve 52 and the water inlet valve 2A to inject water into the glass water tank 2 of the disintegration system until the glass water tank 3 is full, and close the air compressor, the water outlet valve 52 and the water inlet valve 2A at the bottom of the glass water tank 2;

[0078] Step S4: Open the pressurized water inlet valve 2B at the bottom of the glass water tank 2, and apply pressure to the water in the glass water tank 2 through the control panel of the pressurizing system 5;

[0079] Step S5, after the water pressure in the glass water tank 2 reaches the target value and stabilizes, the control program built into the controller 7 is turned on, and according to the experimental requirements, the front bottom plate edge 311, the rear bottom plate edge 312, the left bottom plate edge 313 and the right bottom plate edge 314 are correspondingly retracted to the bottom plate center 310 by controlling the pair of front sliders 342 and / or the pair of rear sliders 343 and / or the pair of left sliders 352 and / or the pair of right sliders in the disintegration box 3, so that one box side wall 3B and / or two box side walls 3B and / or three box side walls 3B and / or four box side walls 3B naturally fall into the water, thereby simulating the conditions of the soil sample 10 being immersed in water on one side and / or two sides and / or three sides and / or four sides, and starting to record the indication value T of the tensiometer 4;

[0080] Step S6, observing the reading of the tensiometer 4, if the reading of the tensiometer 4 does not change or changes by no more than 0.01N for two consecutive hours, it is considered that the soil sample 10 has completely disintegrated;

[0081] Step S7, calculating the mass and disintegration rate of the disintegrated soil;

[0082] The mass m1 of the collapsed soil is calculated according to the following formula (1):

[0083]

[0084] In formula (1), m is the mass of the soil before collapse; T is the reading of the tensiometer; ρ w is the density of water, ρ at room temperature w =1.0×103kg / m 3 ρ s is the natural density of the soil;

[0085] Formula (1) is derived from the mass of the soil before collapse m = the mass of the collapsed soil m1 + the mass of the uncollapsed soil m2, and the force on the uncollapsed soil in water is expressed by the following formula:

[0086]

[0087] In the above formula, F 浮 is the buoyancy of the undisintegrated soil in water;

[0088] The disintegration rate v was calculated according to the following formula (2):

[0089]

[0090] In formula (2), t is the time interval set for recording the reading of the dynamometer.

[0091] The above embodiments are only used to illustrate the present invention, rather than to limit the present invention. Those skilled in the relevant technical field may make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should also belong to the scope of the present invention and should be defined by the claims.

Claims

1. A soil disintegration test device, comprising a disintegration system, a water injection system, a pressurization system and a controller; characterized in that: The disintegration system comprises a support, a glass water tank, a disintegration box and a tensiometer; The bracket includes a bracket bottom plate, a bracket base fixed to the center of the bracket bottom plate, four bracket columns fixed to the four corners of the bracket bottom plate, and a bracket top plate fixed to the tops of the four bracket columns; The glass water tank is fixed on the support base, a water inlet and a pressurized water inlet are provided on the bottom plate of the glass water tank, and a cover plate is connected to the top of the glass water tank through a lifting mechanism; The disintegration box contains a soil sample and includes a box frame and four box side walls; wherein, The box frame includes a box bottom plate, a box top plate and four box support columns; the box bottom plate includes a bottom plate center, a front bottom plate edge, a rear bottom plate edge, a left bottom plate edge and a right bottom plate edge; the bottom plate center is a rectangular box-shaped structure and includes a panel, a receiving plate and front, rear, left and right side plates connected one by one between the front, rear, left and right sides of the panel and the receiving plate; an upper slot is correspondingly provided at the upper part of the front and rear side plates; a lower slot is correspondingly provided at the lower part of the left and right side plates; the front bottom plate edge and the rear bottom plate edge are moved forward and backward by a mechanism The upper part of the front side plate and the upper part of the rear side plate are connected one by one to the left bottom plate edge and the right bottom plate edge through a left-right moving mechanism; the box top plate includes a top plate center part and a front top plate edge, a rear top plate edge, a left top plate edge and a right top plate edge fixedly connected to the front, rear, left and right sides of the top plate center part one by one, and a hollow rod is vertically connected to the center of the top surface of the top plate center part; four box support columns are connected one by one between the four corners outside the bottom plate center part and the four corners outside the top plate center part; The forward and backward moving mechanism includes a pair of forward and backward slide rails, a pair of front sliders and a pair of rear sliders; the pair of forward and backward slide rails are fixed one-to-one to the upper part of the left plate and the upper part of the right plate; the pair of front sliders are installed one-to-one at the front part of the pair of forward and backward slide rails, the pair of front sliders are respectively connected one-to-one with the rear end surfaces of the two ends of the edge of the front bottom plate through a pull rod, and the two ends of the edge of the front bottom plate are respectively slidably installed on the pair of forward and backward slide rails; the pair of rear sliders are installed one-to-one at the rear part of the pair of forward and backward slide rails, the pair of rear sliders are respectively connected one-to-one with the front end surfaces of the two ends of the edge of the rear bottom plate through a pull rod, and the two ends of the edge of the rear bottom plate are respectively slidably installed on the pair of forward and backward slide rails; The left-right moving mechanism comprises a pair of left-right sliding rails, a pair of left sliders and a pair of rear sliders; the pair of left-right sliding rails are fixed one-to-one to the lower part of the front side plate and the lower part of the rear side plate; a pair of left sliders are installed one-to-one to the left part of the pair of left-right sliding rails, the pair of left sliders are respectively connected one-to-one to the right end faces of the two ends of the edge of the left bottom plate through a pull rod, and the two ends of the edge of the left bottom plate are respectively slidably installed on the pair of left-right sliding rails; a pair of right sliders are installed one-to-one to the right side of the pair of left-right sliding rails, the pair of right sliders are respectively connected one-to-one to the left end faces of the two ends of the edge of the right bottom plate through a pull rod, and the two ends of the edge of the right bottom plate are respectively slidably installed on the pair of left-right sliding rails; The front slider, rear slider, left slider and rear slider are all electrically controlled sliders; Four box side walls are arranged one by one between the edge of the front bottom plate and the edge of the front top plate, between the edge of the rear bottom plate and the edge of the rear top plate, between the edge of the left bottom plate and the edge of the left top plate, and between the edge of the right bottom plate and the edge of the right top plate; The disintegration box is arranged in the middle of the glass water tank, and the upper end of the hollow rod passes through the cover plate of the glass water tank; The tension gauge is installed in the middle of the hollow rod, and the signal line of the tension gauge is passed through the hollow rod; The water injection system includes a water tank, an air inlet valve arranged at the top of the water tank, and a water outlet valve arranged at the bottom of the water tank; the inlet of the air inlet valve is connected to the air compressor; the outlet of the water outlet valve is connected to the water inlet of the glass water tank through a water inlet pipe; The pressurizing system is connected to the pressurizing water inlet of the glass water tank through a pressurizing water inlet pipe; The controller is respectively connected to the dynamometer, the front-rear moving mechanism, the left-right moving mechanism and the pressurizing system by signals.

2. The soil collapse test device according to claim 1, characterized in that: The lifting mechanism comprises two lifting ears, two pairs of fixed pulleys, two upright cylinders, two groups of weights and two steel cables; the two lifting ears are symmetrically fixed on the top surface of the cover plate of the glass water tank, one on the left and one on the right; the two pairs of fixed pulleys are fixed on the bottom surface of the bracket top plate one by one and are located above the two lifting ears one by one; the two upright cylinders are fixed on the bracket bottom plates on the left and right sides of the glass water tank one by one; the two groups of weights are arranged in the two upright cylinders one by one; one ends of the two steel cables are connected to the top ends of the two groups of weights one by one, and the other ends of the two steel cables are connected to the two lifting ears after passing through the two pairs of fixed pulleys one by one.

3. The soil collapse test device according to claim 1, characterized in that: The water injection system also includes a steel frame for mounting the water tank.

4. A soil disintegration test method, based on the soil disintegration test device according to claim 1, characterized in that: The test method comprises the following steps: Step S1, cutting the soil sample according to the shape of the disintegration box and measuring the parameters of the soil sample; the parameters of the soil include the mass m of the soil before disintegration and the natural density ρ of the soil s ; Step S2, firstly, the cover plate of the glass water tank is raised by adding the weight of two sets of weights, then the soil sample is placed in the box frame of the disintegration box, and then the four box side walls of the disintegration box are arranged one by one between the edge of the front bottom plate and the edge of the front top plate, between the edge of the rear bottom plate and the edge of the rear top plate, between the edge of the left bottom plate and the edge of the left top plate, and between the edge of the right bottom plate and the edge of the right top plate, so that the disintegration box remains airtight, and then the cover plate of the glass water tank is pulled down by reducing the weight of the two sets of weights, so that the glass water tank is sealed; Step S3, connecting the air compressor to the air inlet valve of the water injection system, setting the pressure, opening the water outlet valve to inject water into the glass water tank of the disintegration system until the glass water tank is full, and then closing the air compressor and the water outlet valve; Step S4: applying pressure to the water in the glass water tank through a pressurizing system; Step S5, after the water pressure in the glass water tank reaches the target value and stabilizes, the control program built into the controller is turned on, and the front bottom plate edge, the rear bottom plate edge, the left bottom plate edge, and the right bottom plate edge are retracted to the center of the bottom plate one by one by controlling a pair of front sliders and / or a pair of rear sliders and / or a pair of left sliders and / or a pair of right sliders in the disintegration box, so that one box side wall and / or two box side walls and / or three box side walls and / or four box side walls fall naturally into the water, thereby simulating the condition that the soil sample is immersed in water on one side and / or two sides and / or three sides and / or four sides, and starting to record the indication value T of the tensiometer; Step S6, observing the reading of the tensiometer, if the reading of the tensiometer does not change or changes by no more than 0.01N for two consecutive hours, it is considered that the soil sample has completely disintegrated; Step S7, calculating the mass and disintegration rate of the disintegrated soil; The mass m1 of the collapsed soil is calculated according to the following formula (1): In formula (1), m is the mass of the soil before collapse; T is the reading of the tensiometer; ρ w is the density of water, ρ at room temperature w =1.0×103kg / m 3 ρ s is the natural density of the soil; According to the following formula (2), soil disintegration rate v: In formula (2), t is the time interval set for recording the reading of the dynamometer.

5. The soil disintegration test method according to claim 4, characterized in that: When performing step S1, the mass m of the soil before collapse is measured using a mechanical balance with an accuracy of 0.001 g; the natural density ρ of the soil s Measured by the ring knife method.

6. The soil disintegration test method according to claim 4, characterized in that: When performing step S7, formula (1) is obtained based on the mass m of the soil before collapse = the mass m1 of the collapsed soil + the mass m2 of the uncollapsed soil, and the force exerted on the uncollapsed soil in water is expressed by the following formula: In the above formula, F 浮 It is the buoyancy of uncollapsed soil in water.

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