A method and apparatus for testing a prototype of a bladder

Abstract

The present application relates to a kind of bag pressure prototype test method and test device in geotechnical engineering test field, the test device mainly includes seven parts of sealing bag (7), wall protection pipe (10), inclinometer tube (6), inclinometer, sealing connection (12), fluid input / output device (9) and fluid pressure measuring device (14), test method uses the fluid pressure in sealing bag (7) to apply test load, uses inclinometer tube (6) and inclinometer to determine lateral displacement response after test loading, uses wall protection pipe (10) to maintain test hole shape, uses granular solid filled between test hole (5) and sealing bag (7) to transmit test loading to rock-soil body, the present application is high in test precision, result is reliable, good stability, low cost, easy to popularize and apply.

Description

Technical Field

[0001] This invention relates to a prototype test method and apparatus for bladder compression in the field of geotechnical engineering testing. Background Technology

[0002] Soil and rock masses are naturally formed materials, and their material components and the interactions between these components vary from place to place. Due to the massive volume, variable composition, and complex mechanical relationships of soil and rock materials, calculations and analyses based on in-situ test data from sampling tests or small-area localized loading have low accuracy and cannot meet engineering requirements, resulting in massive engineering waste and potential safety hazards. Prototype tests, which are feasible, cost-effective, and time-efficient, utilize stress levels close to actual usage conditions and are applied to rock or soil masses under clearly defined boundary conditions. Measuring the deformation response under these loading conditions allows for high-precision determination of the stress-strain relationship in rock or soil masses. This provides reliable parameter data for geotechnical engineering calculations and analyses, representing a pressing scientific and technological challenge in the field of geotechnical engineering. Summary of the Invention

[0003] The first objective of this invention is to provide a method for a bladder compression prototype test. This method utilizes a bladder filled with fluid to apply a sufficiently large load to a rock or soil mass, thereby causing the rock or soil mass to deform sufficiently within a certain distance range. The rock or soil mass within a specific range is treated as a common load-bearing body and undergoes displacement. By measuring the displacement, the stress-deformation characteristics of the rock or soil mass under loads comparable to those used in engineering applications can be determined, thus establishing the stress-strain relationship of the rock or soil mass. This method has low testing costs, high speed, high reliability, and is easy to implement.

[0004] This method for prototype cyst compression testing includes the following steps:

[0005] a) Based on the test objective, determine the maximum load, graded load, unloading requirements, single-stage loading lateral displacement test requirements, lateral displacement stability criteria after single-stage loading, and termination loading criteria, and drill holes in the rock or soil as test holes.

[0006] b) Place the protective tube and the inclinometer tube, whose outer diameter is smaller than the diameter of the test hole formed in step a), into the test hole, and place the inclinometer tube outside the protective tube.

[0007] c) Fill the gap between the outer side of the protective tube and the inclinometer tube and the side wall of the test hole with granular solids;

[0008] d) Using the fluid pressure injected into the sealed bag, the sealed bag is brought into close contact with the granular solids filled in step c);

[0009] e) Apply compressive stress to the sidewall of the test hole constructed in step a) using the sealed bag and the fluid inside the sealed bag, calculate the magnitude of the compressive stress, and meet the graded loading requirements determined in step a) to complete the single-stage loading.

[0010] f) According to the lateral displacement test requirements determined in step a), use an inclinometer and inclinometer tube to measure the lateral displacement generated by the compressive stress applied in step e) on the sidewall of the test hole until the lateral displacement after loading in step e) meets the single-stage loading stability standard determined in step a).

[0011] g) Perform the next level of loading, repeating steps e) to f) until the termination loading criterion determined in step a) is met.

[0012] In the above-mentioned bladder compression prototype test method, in step g), after loading is completed, the bladder compression prototype unloading test is completed in the following manner: the fluid pressure inside the sealed bag is reduced in stages to complete the staged unloading; the lateral displacement of the sidewall of the test hole under the compressive stress after unloading is measured using an inclinometer and inclinometer tube; the next stage of unloading is carried out until unloading is completed.

[0013] In the above-described prototype test method for bladder compression, in step b), the sealing bag is placed over the outside of the protective tube.

[0014] In the above-mentioned bladder compression prototype test method, in step a), a clinometer hole is constructed in the soil and rock mass near the test hole. In steps f) and g), the lateral displacement of the deep soil mass is measured simultaneously, and the horizontal distance between the test hole and the clinometer hole on each horizontal plane is calculated.

[0015] In the above-mentioned prototype test method for bladder compression, in step d), a rod is set inside the sealed bag to prevent the sealed bag from moving up and down, and the sealed bag is placed inside the protective tube. After the sealed bag is filled with fluid, the protective tube is pulled out.

[0016] In the above-mentioned bladder compression prototype test method, in step g), the difference in the test hole sidewall displacement test values ​​of the same soil layer under different seepage path conditions is used to calculate the soil deformation and time correlation parameters.

[0017] In the above-mentioned bladder compression prototype test method, in step g), the measured loading duration at each test point is divided by the square of the equivalent seepage diameter to normalize the effect of seepage conditions, so as to eliminate the difference in test parameters caused by the consolidation of the soil and rock mass or shorten the test time.

[0018] The second objective of this invention is to provide a prototype testing device for bladder compression, which can perform prototype testing on soil and rock masses, has reliable performance, simple operation, high testing accuracy, and low cost.

[0019] This prototype pressure testing device comprises seven parts: a sealed bag, a protective tube, an inclinometer tube, an inclinometer, a sealing connection, a fluid input / output device, and a fluid pressure measuring device. The sealed bag is a bag-shaped component made of a flexible, waterproof fabric with sealing properties. The fluid pressure measuring device is a device for measuring fluid pressure. The fluid input / output device is a device for inputting or outputting fluid into or out of the sealed bag. The sealing connection is a component that connects the sealed bag to the fluid input / output device. The protective tube is a component placed inside or outside the sealed bag to maintain the stability of granular solids on the outside of the sealed bag. The inclinometer tube is placed outside the sealed bag. The sealing connection is located between the sealed bag and the fluid input / output device.

[0020] In the above-mentioned prototype test apparatus for bladder compression, coarse sand filler is placed between the inclinometer tube and the sealing bag.

[0021] In the aforementioned prototype test apparatus for bladder compression, the aforementioned protective tube is placed inside the sealed bag, and a displacement sensor is installed on the outside of the protective tube.

[0022] The prototype compression test method and apparatus of the present invention can apply a huge load to the soil and rock mass by combining water and air, so that the load level borne by the soil and rock mass during the test is comparable to the load level borne in actual engineering. Thus, the displacement test values ​​during the test are comparable to the actual values ​​in engineering practice. Therefore, it is called a prototype test. The test equipment is simple, highly accurate, low in cost, and highly reliable. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the test hole, inclinometer hole, and soil layer distribution profile used in a prototype bladder compression test according to an embodiment of the present invention.

[0024] Figure 2 This is a schematic cross-sectional view of the prototype bladder compression testing device used in one embodiment of the present invention;

[0025] Figure 3 This is a schematic diagram of the first step of the prototype test method for bladder compression used in an embodiment of the present invention;

[0026] Figure 4 This is a schematic diagram of the second step of the prototype compression test method used in an embodiment of the present invention;

[0027] Figure 5 This is a schematic diagram of the third step of the prototype compression test method used in an embodiment of the present invention;

[0028] Figure 6 This is a schematic diagram of the fourth step of the prototype bladder compression test method used in an embodiment of the present invention. Detailed Implementation

[0029] As an embodiment of the present invention, the following is combined with Figures 1-6 This paper introduces the structure and working principle of the prototype test method and test device for bladder compression of the present invention. First, combined with... Figure 2 and Figure 6The structure and working principle of the bladder compression prototype test device of the present invention are introduced. The bladder compression prototype test device includes seven parts: a sealed bag (7), a protective tube (10), an inclinometer (6), an inclinometer, a sealing connection (12), a fluid input / output device (9), and a fluid pressure measuring device (14). The sealed bag (7) is a bag-shaped component with sealing performance, made of flexible cloth-like waterproof material. The fluid pressure measuring device (14) is a device with the function of measuring fluid pressure. The fluid input / output device (9) is a device with the function of inputting or outputting fluid into or out of the sealed bag (7). The sealing connection (12) is a component that connects the sealed bag (7) and the fluid input / output device (9). The inclinometer (6) is placed on the outside of the sealed bag (7). The protective tube (10) is a component placed on the inside or outside of the sealed bag (7) with the function of maintaining the stability of the granular solids on the outside of the sealed bag. The sealing connection (12) is located between the sealed bag (7) and the fluid input / output device (9). In this embodiment, when the protective tube (10) is located inside the sealed bag (7), the inclinometer tube (6) can be placed outside the sealed bag (7) and inserted into the test hole (5) for testing. The protective tube (10) can also be placed outside the sealed bag (7). In this case, the inclinometer tube (6) can be placed outside the protective tube (10) and inserted into the test hole (5), then sand is filled, and the sealed bag (7) is placed inside the protective tube (10). Before the test load is applied, the protective tube (10) is pulled out, and the sealed bag (7) is left in the test hole (5). In this embodiment, fluid (8) is supplied into the sealed bag (7) using a fluid input / output device (9) to increase the pressure of the fluid (8) inside the sealed bag (7), thereby achieving test loading. The pressure of the fluid (8) inside the sealed bag (7) is measured using a fluid pressure measuring device (14) to determine the magnitude of the test load. Then, the change in the diameter of the test hole and the lateral displacement of the soil under the test loading are measured using a clinometer (6) and a clinometer, thus achieving the test objective of measuring the soil deformation response under the action of bagged fluid load. In this embodiment, the fluid input / output device (9) can be a pressure-stabilizing hydraulic pump or an air compressor, and the corresponding fluid pressure measuring device (14) can be a hydraulic gauge or a pneumatic gauge. In this embodiment, the fluid input / output device (9) can also be a water tower or a water storage tank installed at a high place, and the corresponding fluid pressure measuring device (14) can be a height difference measuring device. In this embodiment, to avoid the adverse effects of shallow backfill during the test, a sealing connection (12) can be used to isolate the backfill at the top of the sealing bag (7). The sealing connection (12) can be made of steel pipe. Coarse sand (11) can be used to fill the space between the sealing connection (12) and the side wall of the test hole (5) to prevent local rupture of the sealing bag (7). In this embodiment, materials such as... Figure 2The top ring (13) shown fixes the top of the inclinometer tube (6) relative to the top, serving as a reference point for measuring the lateral deformation of the inclinometer tube (6) and improving the accuracy of the test measurement. The top ring (13) can be made of reinforced concrete or steel pipe concrete. In this embodiment, the protective tube (10) can be placed inside the sealing bag (7). After the sealing bag (7) is filled with fluid (8), it can come into close contact with the backfill material on the outside. In this embodiment, the protective tube (10) can also be placed outside the sealing bag (7). After the sealing bag (7) is filled with fluid of sufficient pressure, the protective tube (10) is pulled out, so that the sealing bag comes into close contact with the backfill material. In this embodiment, the protective tube (10) can be placed inside the sealing bag (7), and a displacement sensor can be installed on the outside of the protective tube (10) to measure the cross-sectional dimensions of the sealing bag (7) in real time during the test.

[0030] The following parts of this embodiment are mainly combined with Figures 1-6 This paper introduces the specific implementation method and steps of the prototype test method for bladder compression of the present invention. The first step is to determine the maximum loading amount, the graded loading amount and the graded unloading amount, the lateral displacement test requirements for single-stage loading and unloading, the lateral displacement stability criteria after single-stage loading and unloading, the termination loading criteria, and the termination unloading criteria according to the test objectives. Holes are then drilled in the rock or soil as test holes (5). Figure 1 and Figure 3 As shown, when unloading test results are not required, only loading control requirements can be set in this step. The loading amount in this step can be determined by referring to the actual load size of the project and the purpose of the test. The determination of graded loading, graded unloading, and loading / unloading stability criteria can be selected by referring to the relevant regulations for static load tests. In this step, the maximum compressive stress in the termination loading criterion can be matched with the magnitude of the actual additional stress in the rock or soil mass of the proposed project at the test site. Lateral displacement test requirements can be performed by referring to the requirements and standards for lateral displacement measurement in deep soil. In this embodiment, the soil layer distribution of the selected test site is as follows: Figure 1 As shown, the soil includes a fill layer (1), a sandy silt layer (2), a silty clay layer (3), and a silty sand layer (4). In this step, an inclinometer tube (6) is installed in the soil near the test hole (5), as shown. Figure 1 As shown. After completing the first step, proceed to the second step. Place the protective tube (10), whose outer diameter is smaller than the diameter of the test hole (5) formed in the first step, and the inclinometer tube (6) into the test hole (5), so that the inclinometer tube (6) is located outside the protective tube (10), as shown. Figure 4As shown. In this step, when installing the inclinometer tube (6), the inclinometer tube (6) can be fixed relatively around the periphery of the protective tube (10), so that the inclinometer tube (6) is evenly distributed around the periphery of the protective tube (10), and the protective tube (10) and the inclinometer tube (6) can move relative to each other in the vertical direction, which facilitates the removal of the protective tube (10). After completing the second step, proceed to the third step. In this step, coarse sand is used as a granular solid to fill the gap between the outer side of the protective tube (10) and the inclinometer tube (6) and the side wall of the test hole (5), such as Figure 5 As shown. When the protective tube (10) is located outside the sealing bag (7), during the sand filling process, it is necessary to prevent the sand from entering the inside of the protective tube (10). The protective tube (10) can be inserted into the soil at the bottom of the test hole (5) to a certain depth to solve this problem. After completing the third step, proceed to the fourth step. In this step, the fluid pressure injected into the sealing bag (7) is used to make the sealing bag (7) and the granular solid filled in the third step come into close contact. In this step, when the protective tube (10) is located outside the sealing bag (7), the space inside the protective tube (10) needs to be filled with the sealing bag (7) and the fluid (8) injected into the sealing bag (7), and then the protective tube (10) is pulled out. The cross-sectional view of the test hole after this step is completed is shown in the figure. Figure 6 As shown. The key point of this step is that when the protective tube (10) needs to be pulled out, it is necessary to prevent sand from entering the space inside the protective tube (10). This can be achieved by the following method: before the protective tube (10) is pulled out, fill the sealing bag (7) with water and completely fill the space inside the protective tube (10) with the sealing bag (7) and water; set a rod inside the sealing bag (7) to prevent the sealing bag (7) from moving up and down during the process of pulling out the protective tube (10). In this step, the fluid (8) can be a combination of water and air. After completing the fourth step, proceed to the fifth step. In this step, the sealing bag (7) and the fluid (8) inside the sealing bag (7) are used to apply compressive stress to the side wall of the test hole (5) constructed in the first step, calculate the magnitude of the compressive stress, and meet the graded loading requirements determined in the first step to complete the single-stage loading. In this step, because the soil will deform after loading, fluid (8) should be replenished into the sealed bag (7) in real time. A pressure-stabilizing pump can be used to replenish the fluid (8), or a water tower connected to the sealed bag (7) or a water storage tank higher than the test site can be used to replenish the fluid (8). After completing the fifth step, proceed to the sixth step. In this step, according to the lateral displacement test requirements determined in the first step, the lateral displacement of the sidewall of the test hole (5) under the loading compressive stress in the fifth step is measured using an inclinometer and inclinometer tube (6) until the lateral displacement after loading in the fifth step meets the single-stage loading stability standard determined in the first step. In this step, when multiple inclinometer tubes (6) are buried, the interval time for measuring each inclinometer tube (6) should be shortened as much as possible. When multiple inclinometer tubes (6) are buried in the soil and rock mass around the test hole (5), the lateral displacement of the sidewall of the test hole (5) under the loading compressive stress in the fifth step is measured. Figure 1When using the inclinometer tube (6) shown, measurements should be taken simultaneously. After completing step six, proceed to step seven. This step is a repetitive step, repeating steps five and six until the termination loading criterion determined in step one is met. In this step, after loading is completed, the prototype unloading test of the bladder pressure can be completed as follows: according to the determined graded unloading amount, start to reduce the pressure of the fluid (8) in the sealed bag (7) in stages to complete the graded unloading; use the inclinometer and inclinometer tube (6) to measure the lateral displacement of the sidewall of the test hole (5) under the action of compressive stress after unloading until the lateral displacement after unloading meets the determined lateral displacement stability criterion after single-stage unloading; proceed to the next stage of unloading until unloading is completed. In this step, the difference in the test hole sidewall displacement test values ​​under different seepage path conditions of the same soil layer can be used to calculate the soil deformation and time correlation parameters. In this step, the measured loading duration of each test point can also be divided by the square of the equivalent seepage path to normalize the influence of seepage conditions, so as to eliminate the difference in test parameters caused by soil consolidation or shorten the test time. Thus, the prototype test method for bladder compression of the present invention is completed.

[0031] This patent includes, but is not limited to, other similar methods and apparatus that can be used by those skilled in the art.

Claims

1. A method for prototype bladder compression testing, comprising the following steps: a) Based on the test objective, determine the maximum load, graded load, unloading requirements, single-stage loading lateral displacement test requirements, single-stage loading lateral displacement stability standard, and termination loading standard, and drill holes in the rock or soil as test holes (5). b) Place the protective tube (10) with an outer diameter smaller than the diameter of the test hole (5) formed in step a) and the inclinometer tube into the test hole, and make the inclinometer tube located outside the protective tube (10); c) Fill the gap between the outer side of the protective tube (10) and the inclinometer tube and the side wall of the test hole (5) with granular solids; d) Using the fluid pressure injected into the sealed bag (7), the sealed bag (7) is brought into close contact with the granular solid filled in step c); e) Apply compressive stress to the sidewall of the test hole (5) constructed in step a) using the sealed bag (7) and the fluid inside the sealed bag (7), calculate the magnitude of the compressive stress, and meet the graded loading requirements determined in step a) to complete the single-stage loading; f) According to the lateral displacement test requirements determined in step a), use the inclinometer and inclinometer tube to measure the lateral displacement of the sidewall of the test hole (5) under the compressive stress applied in step e), until the lateral displacement after loading in step e) meets the single-stage loading stability standard determined in step a). g) Perform the next level of loading, repeating steps e) to f) until the termination loading criterion determined in step a) is met.

2. The capsule pressure prototype test method of claim 1, characterized in that In step g), after loading is completed, the unloading test is completed in the following manner: the fluid pressure inside the sealed bag (7) is reduced in stages to complete the staged unloading; the lateral displacement of the sidewall of the test hole (5) under the action of compressive stress after unloading is measured using an inclinometer and an inclinometer tube; the next stage of unloading is carried out until the unloading is completed.

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