Method for quantitatively distinguishing between wet collapse and solution collapse of wet collapsible soil under rated pressure

Abstract

The application discloses a kind of quantitative differentiation wet collapse soil under rated pressure in wet collapse and collapse determination method, comprising the following steps: one, sampling and preparation ring knife undisturbed soil sample;Two, different solution's water immersion consolidation test;Three, the additional subsidence of unit thickness of undisturbed soil sample under rated pressure is calculated;Four, the quantitative calculation of undisturbed soil sample under rated pressure in unit thickness of collapse is carried out by difference subtraction;Five, the determination of wet collapse and collapse predominance under rated pressure.The application step is simple, operability is strong, test cycle is short, by using undisturbed soil sample to carry out test by using different solution to separate wet collapse, and then quantitative differentiation wet collapse and collapse under rated pressure, on this basis, by interval setting of wet collapse coefficient, collapse coefficient and total subsidence coefficient, qualitative determination of the predominance of wet collapse and collapse under rated pressure can effectively solve the problem of qualitative quantitative differentiation of wet collapse and collapse in geotechnical engineering.

Description

Technical Field

[0001] This invention belongs to the field of soil layer characteristic research technology, specifically relating to a method for quantitatively distinguishing between wet collapse and solution collapse of soil under rated pressure. Background Technology

[0002] Currently, the methods used in building technical specifications for saline soil areas at home and abroad to obtain the collapse coefficient are basically the same as those used in collapsibility tests. However, it is impossible to qualitatively and quantitatively determine whether the collapse of saline soil contains collapsibility. In recent years, most domestic and foreign studies have focused on independent research on collapsibility and solution using salt washing and remolding sample tests. However, these studies suffer from problems such as long test cycles, large errors in test results, and the inability to provide objective evaluation. Qualitatively and quantitatively distinguishing between collapsibility and solution in collapsible soil has become a difficult problem in the geotechnical engineering field.

[0003] Therefore, there is an urgent need for a method that is simple in procedure, short in cycle, and reasonably designed to qualitatively and quantitatively distinguish between collapsibility and solution collapse under rated pressure in collapsible soil, and to solve the problem that existing technologies cannot directly use undisturbed samples to qualitatively and quantitatively determine collapsibility and solution collapse under rated pressure in collapsible soil. Summary of the Invention

[0004] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing a method for quantitatively distinguishing between wet collapse and solution collapse in collapsible soil under rated pressure. The method is simple in steps, using distilled water and saturated NaCl solution to conduct immersion consolidation tests under rated pressure, thereby quantitatively distinguishing between wet collapse and solution collapse under rated pressure. Based on the quantitative distinction between wet collapse and solution collapse under rated pressure, by setting the ranges of the wet collapse coefficient, solution collapse coefficient, and total settlement coefficient, the dominance of wet collapse and solution collapse under rated pressure can be qualitatively determined. Furthermore, the method proposes a method for determining whether to use the total settlement calculation as the solution collapse amount or the wet collapse amount, which can effectively solve the problem of the difficulty in quantitatively distinguishing between wet collapse and solution collapse in collapsible soil in geotechnical engineering.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for quantitatively distinguishing between wet collapse and solution collapse of collapsible soil under rated pressure, characterized in that the method includes the following steps: Step 1: Sampling and Preparation of Uncircular Soil Samples: Take one undisturbed soil sample from the soil layer to be evaluated and prepare two samples with a height of [missing information]. The undisturbed soil samples from the ring cutter, namely the first undisturbed soil sample from the ring cutter and the second undisturbed soil sample from the ring cutter. Step 2: Immersion Consolidation Test with Different Solutions: Using distilled water as the solution, an immersion consolidation test was conducted on the undisturbed soil sample of the first ring cutter under the rated pressure P. The stable settling height of the undisturbed soil sample of the first ring cutter under the rated pressure P was obtained. ; Using saturated NaCl solution as the solution, a consolidation test was conducted on the undisturbed soil sample of the second ring cutter under the rated pressure P by immersion in saturated NaCl solution. The stable settling height of the undisturbed soil sample of the second ring cutter under the rated pressure P was obtained. ; Step 3: Calculate the additional settlement per unit thickness of the undisturbed soil sample under rated pressure. The process is as follows: Using the formula... The additional settlement per unit thickness of the first ring cutter undisturbed soil sample using distilled water as the solution was calculated under rated pressure. ,in, The settling stability height of the undisturbed soil sample under rated pressure P is the height of the ring cutter under water immersion. Using formula The additional settlement per unit thickness of the second ring cutter undisturbed soil sample using saturated NaCl solution as the solution was calculated under rated pressure. ; Step 4: Quantitatively calculate the amount of solution collapse per unit thickness of the undisturbed soil sample under rated pressure using the difference method: Using the formula... The amount of solution collapse per unit thickness of the undisturbed soil sample under rated pressure was calculated. ; Step 5: Determining the dominance of wet collapse and solution collapse under rated pressure, the process is as follows: when <0.01 and If the value is ≥0.015, the soil layer is determined to be collapsible saline soil under rated pressure. As a collapsibility coefficient, it is used to calculate the collapsibility of the soil layer it represents; when <0.005, 0.01≤ <0.015 and If the value is ≥0.015, the soil layer is determined to be saline soil that can be considered as collapsible under rated pressure. As a collapsibility coefficient, it is used to calculate the collapsibility of the soil layer it represents; When 0.005≤ <0.01, <0.01 and 0.01≤ If the value is less than 0.015, the soil layer is determined to be saline soil that can be considered as collapsible under rated pressure. As a solution collapse coefficient, the amount of solution collapse of the soil layer it represents is calculated. when ≥0.01、 If the value is less than 0.015, the soil layer is determined to be saline soil with collapsibility under rated pressure. As a solution collapse coefficient, the amount of solution collapse of the soil layer it represents is calculated. When 0.005≤ <0.01, 0.005< <0.015, and 0.015≤ When <0.025, the soil layer is determined to be saline soil that can be considered as collapsible and soluble under rated pressure; when ≥0.01、 When the value is ≥0.015, the soil layer is determined to be saline soil with collapsibility and solubility under rated pressure; when <0.01, <0.01, and If the value is less than 0.01, the soil layer is determined to be saline soil that does not exhibit collapsibility or solubility under rated pressure, and is classified as ordinary saline soil. It is used as a deformation coefficient to calculate the deformation of the soil layer it represents.

[0006] The above-mentioned quantitative method for distinguishing between wet collapse and solution collapse of collapsible soil under rated pressure is characterized in that: in step two, the process of conducting water immersion consolidation tests on the first and second ring cutter undisturbed soil samples is as follows: Step 201: Level the consolidation apparatus and simultaneously move the dial indicator head to ensure that the dial indicator pointer and measuring rod can rotate freely. Step 202: For the two ring cutter undisturbed soil samples, place them at the bottom of the consolidation container in the following order: retaining ring, lower permeable stone, first thin filter paper, ring cutter undisturbed soil sample, guide ring, second thin filter paper, upper permeable stone, and pressure cover plate. Place the consolidation container on the consolidation apparatus platform, and attach the bottom of the crossbeam of the consolidation apparatus to the top of the pressure cover plate. Install a dial gauge at the center of the crossbeam. Step 203: Apply a pre-pressure of 1 kPa to make the two undisturbed soil samples of the ring cutter fully contact their corresponding first bottom permeable stone and first top permeable stone, and adjust the dial gauges corresponding to the two undisturbed soil samples of the ring cutter to the initial reading. Step 204: After pressurizing the two undisturbed soil samples with ring cutters to the rated pressure, read the deformation reading of each undisturbed soil sample with ring cutters every 30 minutes until the deformation of the two undisturbed soil samples with ring cutters is stable. Step 205: Inject distilled water into the water tank where the first ring cutter undisturbed soil sample is located, and inject distilled water up to the height of the top surface of the permeable stone until the deformation of the first ring cutter undisturbed soil sample stabilizes. Saturated NaCl solution was injected into the water tank where the second ring cutter undisturbed soil sample was located, and the saturated NaCl solution was injected up to the height of the top permeable stone until the deformation of the second ring cutter undisturbed soil sample stabilized. Step 206: After the immersion consolidation test is completed, remove the first and second ring cutter undisturbed soil samples.

[0007] The above-mentioned quantitative method for distinguishing between wet collapse and collapse determination of wet collapsible soil under rated pressure is characterized in that: in step 205, before the deformation of the undisturbed soil sample of the first ring cutter stabilizes, distillation is promptly added to the water tank where the undisturbed soil sample of the first ring cutter is located, so that the water head in the water tank where the undisturbed soil sample of the first ring cutter is located is the same as that at the top of the permeable stone. Before the deformation of the undisturbed soil sample of the second ring cutter stabilizes, saturated NaCl solution should be added to the water tank containing the undisturbed soil sample of the second ring cutter in a timely manner, so that the water head in the water tank containing the undisturbed soil sample of the second ring cutter and the top of the permeable stone are kept at the same level.

[0008] The above-mentioned quantitative method for distinguishing between wet collapse and collapse determination of collapsible soil under rated pressure is characterized in that: in step 205, before the deformation of the first ring cutter undisturbed soil sample stabilizes, the distilled water in the water tank where the first ring cutter undisturbed soil sample is located is replaced at set intervals; at the same time, before the deformation of the second ring cutter undisturbed soil sample stabilizes, the saturated NaCl solution in the water tank where the second ring cutter undisturbed soil sample is located is replaced at set intervals.

[0009] The above-mentioned quantitative method for distinguishing between collapsible and solution-prone soils under rated pressure is characterized in that: in step five, when the undisturbed soil sample is saline soil that can be considered as collapsible and solution-prone under rated pressure, the saline soil that can be considered as collapsible and solution-prone under rated pressure is classified into saline soil that can be considered as collapsible and saline soil that can be considered as solution-prone according to the degree of dominance of collapsibility and solution-proneness in settlement deformation, that is, when 1.5 ≤ At that time, the soil layer was determined to be saline soil that could be considered collapsible under rated pressure. As a collapsibility coefficient, it is used to calculate the collapsibility of the soil layer it represents; when 1.5 > At that time, the soil layer was determined to be saline soil that could be considered as collapsible under rated pressure. It is used as the solution collapse coefficient to calculate the amount of solution collapse in the soil layer it represents.

[0010] The above-mentioned quantitative method for distinguishing between collapsible and solution-prone soils under rated pressure is characterized in that: in step five, when the undisturbed soil sample is saline soil exhibiting both collapsibility and solution-proneness under rated pressure, the saline soil is classified into collapsibility-dominated saline soil and solution-dominated saline soil based on the degree of dominance of collapsibility and solution-proneness in settlement deformation, i.e., when 1.5... ≤ At that time, the soil layer was determined to be saline soil dominated by collapsibility under rated pressure. As a collapsibility coefficient, it is used to calculate the collapsibility of the soil layer it represents; when 1.5 > At that time, the soil layer was determined to be saline soil dominated by dissolution under rated pressure. The solution coefficient is used to calculate the amount of solution in the soil layer it represents.

[0011] Compared with the prior art, the present invention has the following advantages: 1. The method of the present invention has simple steps, does not require salt washing, is highly operable, has a short experimental cycle, and is novel in design and easy to promote and use.

[0012] 2. This invention uses undisturbed soil samples for testing, and the test is completed without disturbing the undisturbed soil samples. The data obtained is more objective and consistent with reality, and solves the error caused by the damage to the original structure in the remodeling test.

[0013] 3. This invention uses saturated NaCl solution to conduct immersion and saturated consolidation tests, successfully inhibiting the dissolution of crystalline salts and salt solutions in saline soil during the test. It directly and completely separates the subsidence without disturbing the original structure of the saline soil, resulting in more objective and realistic data. It quantitatively distinguishes between subsidence and solution subsidence under rated pressure and provides calculation formulas for the total subsidence coefficient, subsidence coefficient, and solution subsidence coefficient under rated pressure after separation. This facilitates the quantitative determination of subsidence and solution subsidence under rated pressure, enabling objective evaluation of undisturbed soil samples and solving a problem that has hindered the geotechnical engineering community.

[0014] 4. Based on the quantitative distinction between collapsibility and solution collapse under rated pressure, this invention can qualitatively determine the dominance of collapsibility and solution collapse under rated pressure by setting the range of collapsibility coefficient, solution collapse coefficient and total settlement coefficient. It also proposes a method to determine whether to use total settlement as the amount of solution collapse or collapsibility collapse when calculating, which can effectively solve the problem of quantitatively distinguishing between collapsibility and solution collapse in collapsible soils in geotechnical engineering. This can effectively avoid engineering quality problems, engineering cost problems and operation-period problems in saline soil areas.

[0015] In summary, the method of this invention is simple in procedure. By conducting immersion consolidation tests under rated pressure using distilled water and saturated NaCl solution, it quantitatively distinguishes between wet collapse and solution collapse under rated pressure. Based on the quantitative distinction between wet collapse and solution collapse under rated pressure, by setting the ranges for the wet collapse coefficient, solution collapse coefficient, and total settlement coefficient, it is possible to qualitatively determine the dominance of wet collapse and solution collapse under rated pressure. Furthermore, it proposes a method for determining whether to use the total settlement as the amount of solution collapse or wet collapse when calculating the total settlement. This effectively solves the problem of the difficulty in quantitatively distinguishing between wet collapse and solution collapse in soils prone to wet collapse in geotechnical engineering.

[0016] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0017] Figure 1 This is a flowchart of the present invention.

[0018] Figure 2 This is a schematic diagram of the installation structure of the undisturbed soil sample using the ring cutter of the present invention.

[0019] Explanation of reference numerals in the attached figures: Detailed Implementation

[0020] like Figure 1 and Figure 2 The method for quantitatively distinguishing between wet collapse and solution collapse of collapsible soil under rated pressure is characterized by the following steps: Step 1: Sampling and Preparation of Uncircular Soil Samples: Take one undisturbed soil sample from the soil layer to be evaluated and prepare two samples with a height of [missing information]. The undisturbed soil samples from the ring cutter, namely the first undisturbed soil sample from the ring cutter and the second undisturbed soil sample from the ring cutter. It should be noted that when preparing undisturbed soil samples using ring cutters, an ultra-thin soil sampler with authorization announcement number CN214793911 U is used for sampling; alternatively, other soil samplers or manual cutting methods can be used to collect one undisturbed soil sample from the soil layer to be determined. Then, a soil cutting tool and two ring cutters are used to cut the undisturbed soil sample to prepare two ring cutter undisturbed soil samples. The two ring cutter undisturbed soil samples have the same structure and dimensions. The ring cutter used has a height of 20.00 mm, an inner diameter of φ79.8 mm, and an area of ​​5000 mm². 2 The maximum permissible difference in density between two undisturbed soil samples obtained by ring cutter is ±0.015 g / cm³. 3 The maximum permissible difference in moisture content is ±1%.

[0021] Step 2: Immersion Consolidation Test with Different Solutions: Using distilled water as the solution, an immersion consolidation test was conducted on the undisturbed soil sample of the first ring cutter under the rated pressure P. The stable settling height of the undisturbed soil sample of the first ring cutter under the rated pressure P was obtained. ; Using saturated NaCl solution as the solution, a consolidation test was conducted on the undisturbed soil sample of the second ring cutter under the rated pressure P by immersion in saturated NaCl solution. The stable settling height of the undisturbed soil sample of the second ring cutter under the rated pressure P was obtained. ; It should be noted that the rated pressure P is 200 kPa. The stable height of the first ring cutter undisturbed soil sample after immersion in water under the rated pressure P refers to the height of the first ring cutter undisturbed soil sample after immersion consolidation test under the rated pressure P and stabilization.

[0022] Step 3: Calculate the additional settlement per unit thickness of the undisturbed soil sample under rated pressure. The process is as follows: The additional subsidence under rated pressure is calculated by subtracting the submerged subsidence stability height from the unsubmerged subsidence stability height. Therefore, using the formula... The additional settlement per unit thickness of the first ring cutter undisturbed soil sample using distilled water as the solution was calculated under rated pressure. ,in, The settling stability height of the undisturbed soil sample under rated pressure P is the height of the ring cutter under water immersion. Using formula The additional settlement per unit thickness of the second ring cutter undisturbed soil sample using saturated NaCl solution as the solution was calculated under rated pressure. ; It should be noted that the additional settlement per unit thickness (unit height) of the first ring cutter undisturbed soil sample calculated under rated pressure using distilled water as the solution is the total settlement coefficient under rated pressure. The additional settlement per unit thickness of the undisturbed soil sample under rated pressure, calculated using a saturated NaCl solution as the solution, is the collapsibility per unit thickness under rated pressure, also known as the collapsibility coefficient.

[0023] In actual use, the stable settling height of the un-water-immersed soil sample is measured after the undisturbed soil sample has been stabilized by pressure deformation.

[0024] Step 4: Quantitatively calculate the amount of solution collapse per unit thickness of the undisturbed soil sample under rated pressure using the difference method: The additional settlement and total settlement coefficient obtained from the immersion consolidation test of the first ring cutter undisturbed soil sample using distilled water as the solution are a combination of wet collapse and solution collapse. The additional settlement and wet collapse coefficient obtained from the second ring cutter undisturbed soil sample using saturated NaCl solution are the results of the separation. The formula is then used to calculate the solution collapse amount. The amount of solution collapse per unit thickness of the undisturbed soil sample under rated pressure was calculated. It can also be described as the solution collapse coefficient of the undisturbed soil sample under rated pressure; Step 5: Determining the dominance of wet collapse and solution collapse under rated pressure, the process is as follows: when <0.01 and If the value is ≥0.015, the soil layer is determined to be collapsible saline soil under rated pressure. As a collapsibility coefficient, it is used to calculate the collapsibility of the soil layer it represents; when <0.005, 0.01≤ <0.015 and If the value is ≥0.015, the soil layer is determined to be saline soil that can be considered as collapsible under rated pressure. As a collapsibility coefficient, it is used to calculate the collapsibility of the soil layer it represents; When 0.005≤ <0.01, <0.01 and 0.01≤ If the value is less than 0.015, the soil layer is determined to be saline soil that can be considered as collapsible under rated pressure. As a solution collapse coefficient, the amount of solution collapse of the soil layer it represents is calculated. when ≥0.01、 If the value is less than 0.015, the soil layer is determined to be saline soil with collapsibility under rated pressure. As a solution collapse coefficient, the amount of solution collapse of the soil layer it represents is calculated. When 0.005≤ <0.01, 0.005< <0.015, and 0.015≤ When <0.025, the soil layer is determined to be saline soil that can be considered as collapsible and soluble under rated pressure; when ≥0.01、 When the value is ≥0.015, the soil layer is determined to be saline soil with collapsibility and solubility under rated pressure; when <0.01, <0.01, and If the value is less than 0.01, the soil layer is determined to be saline soil that does not exhibit collapsibility or solubility under rated pressure, and is classified as ordinary saline soil. It is used as a deformation coefficient to calculate the deformation of the soil layer it represents; In practice, due to the unique three-phase composition of saline soil, its liquid phase is not water but a saturated salt solution, and the solid phase contains unstable crystalline salts in addition to the solid particles of the soil. The liquid phase can transform into each other due to changes in external conditions. The collapsibility and dissolution mechanisms in saline soil with wet collapsibility are as follows: Collapse mechanism - Under certain pressure, when soil is wetted by water, the soil structure (skeletal particle morphology, connection form and arrangement) is rapidly destroyed, resulting in significant additional settlement; Solution subsidence mechanism - Under certain pressure, due to the dissolution and migration of salts in the soil by water, the crystalline salt particles in the soil are dissolved in the form of solute by the seepage water and carried away with the seepage, resulting in additional subsidence.

[0025] Based on the mechanisms of wet collapse and dissolution, under certain pressure, the salt and saturated salt solution in saline soil with wet collapse properties can be prevented from dissolving and migrating during the immersion process, thus allowing the wet collapse portion to be directly separated.

[0026] The salts in saline soil that dissolve in water are mainly soluble and moderately soluble salts, with the main ion being Na+. + K +Ca 2+ Mg 2+ NH4 + SO4 2- Cl - CO3 2- HCO3 - Based on the solubility and molecular weight of readily soluble and moderately soluble salts, the Na+ concentration per unit volume of water in readily soluble and moderately soluble salt solutions under saturated conditions is... + NH4 + and Cl - The ions account for the largest number, so easily soluble and moderately soluble salts cannot dissolve in saturated NaCl and NH4Cl solutions. Since saturated NH4Cl solutions are unstable and easily decomposed, using saturated NaCl solution as the soaking solution can inhibit the dissolution of easily soluble and moderately soluble salt crystals in saline soil and the conversion between liquid salt solution and crystals in saline soil.

[0027] Therefore, by using saturated NaCl solution as the solution to conduct a water saturation consolidation test on saline soil under a certain pressure, the amount of collapse can be directly separated, and the additional settlement deformation per unit thickness obtained is the collapse coefficient. By using distilled water as the solution to conduct a water saturation consolidation test on saline soil under a certain pressure, the additional settlement deformation per unit thickness obtained is defined as the total deformation coefficient, which includes all the solution collapse per unit thickness. The solution collapse coefficient in wet collapsible soil is obtained by subtraction method, thus completing the qualitative and quantitative distinction between collapse and solution collapse in wet collapsible soil under a certain pressure.

[0028] It should be noted that by using undisturbed soil samples for testing, the data obtained are more objective and consistent with reality, thus solving the error caused by the damage to the original structure in the remodeling test.

[0029] It should be noted that by using saturated NaCl solution for immersion and consolidation tests, the dissolution of crystalline salts and salt solutions in saline soil during the test was successfully suppressed. This ensured that the original structure of the saline soil remained undisturbed, allowing for complete separation of the subsidence. The test quantitatively distinguished between subsidence and solution subsidence under rated pressure and provided calculation formulas for the total subsidence coefficient, subsidence coefficient, and solution subsidence coefficient under rated pressure after separation. This facilitates the quantitative determination of subsidence and solution subsidence under rated pressure, eliminates the need for salt washing, enhances operability, shortens the test cycle, and enables objective evaluation of undisturbed soil samples. The data is more objective and consistent with reality, solving a major problem hindering the geotechnical engineering community.

[0030] It should be noted that, based on the quantitative distinction between collapsibility and solution collapse under rated pressure, the range setting of collapsibility coefficient, solution collapse coefficient, and total settlement coefficient enables a qualitative determination of the dominance of collapsibility and solution collapse under rated pressure. Furthermore, it proposes a method for determining whether to use total settlement as the amount of solution collapse or collapsibility collapse when calculating total settlement. This effectively solves the problem of quantitatively distinguishing between collapsibility and solution collapse in collapsible soils in geotechnical engineering, and can thus effectively avoid engineering quality problems, engineering cost problems, and operational problems in saline soil areas.

[0031] In specific implementation, the process of conducting water immersion consolidation tests on the first and second ring cutter undisturbed soil samples in step two is as follows: Step 201: Level the consolidation apparatus and simultaneously move the dial indicator head to ensure that the dial indicator pointer and measuring rod can rotate freely. Step 202: For the two ring cutter undisturbed soil samples, first place them at the bottom of the consolidation container in the following order: retaining ring 1, lower permeable stone 2, first thin filter paper 3, ring cutter undisturbed soil sample 4, guide ring 5, second thin filter paper 6, upper permeable stone 7, and pressure cover plate. Place the consolidation container on the consolidation apparatus platform, and attach the bottom of the crossbeam of the consolidation apparatus to the top of the pressure cover plate. Install a dial gauge at the center of the crossbeam. Step 203: Apply a pre-pressure of 1 kPa to make the two undisturbed soil samples of the ring cutter fully contact their corresponding first bottom permeable stone and first top permeable stone, and adjust the dial gauges corresponding to the two undisturbed soil samples of the ring cutter to the initial reading. Step 204: After pressurizing the two undisturbed soil samples with ring cutters to the rated pressure, read the deformation reading of each undisturbed soil sample with ring cutters every 30 minutes until the deformation of the two undisturbed soil samples with ring cutters is stable. Step 205: Inject distilled water into the water tank where the first ring cutter undisturbed soil sample is located, and inject distilled water up to the height of the top surface of the permeable stone until the deformation of the first ring cutter undisturbed soil sample stabilizes. Saturated NaCl solution was injected into the water tank where the second ring cutter undisturbed soil sample was located, and the saturated NaCl solution was injected up to the height of the top permeable stone until the deformation of the second ring cutter undisturbed soil sample stabilized. Step 206: After the immersion consolidation test is completed, remove the first and second ring cutter undisturbed soil samples.

[0032] In this embodiment, in step 204, the stabilization condition for the deformation of each ring cutter undisturbed soil sample is that the deformation per hour is no more than 0.01 mm.

[0033] In specific implementation, in step 205, before the deformation of the undisturbed soil sample of the first ring cutter stabilizes, distillation is promptly added to the water tank where the undisturbed soil sample of the first ring cutter is located, so that the water head in the water tank where the undisturbed soil sample of the first ring cutter is located is the same as that at the top of the permeable stone. Before the deformation of the undisturbed soil sample of the second ring cutter stabilizes, saturated NaCl solution should be added to the water tank containing the undisturbed soil sample of the second ring cutter in a timely manner, so that the water head in the water tank containing the undisturbed soil sample of the second ring cutter is the same as that at the top of the permeable stone.

[0034] In specific implementation, in step 205, before the deformation of the first ring cutter undisturbed soil sample stabilizes, the distilled water in the water tank where the first ring cutter undisturbed soil sample is located is replaced at set intervals. At the same time, before the deformation of the second ring cutter undisturbed soil sample stabilizes, the saturated NaCl solution in the water tank where the second ring cutter undisturbed soil sample is located is replaced at set intervals.

[0035] In this embodiment, when replacing the distilled water in the water tank containing the first ring cutter undisturbed soil sample, the distilled water in the water tank containing the first ring cutter undisturbed soil sample is first drained. After the water level in the water tank containing the first ring cutter undisturbed soil sample drops to the minimum set water level, distilled water is re-injected into the water tank containing the first ring cutter undisturbed soil sample until the water head in the water tank containing the first ring cutter undisturbed soil sample is the same as that at the top of the permeable stone. The method for replacing the saturated NaCl solution in the water tank containing the second ring cutter undisturbed soil sample is the same as the method for replacing the distilled water in the water tank containing the first ring cutter undisturbed soil sample.

[0036] In specific implementation, in step five, when the undisturbed soil sample is saline soil that can be considered as collapsible and soluble under rated pressure, the saline soil that can be considered as collapsible and soluble under rated pressure is classified into saline soil that can be considered as collapsible and saline soil that can be considered as soluble based on the degree to which collapsibility and soluble collapse dominate the settlement deformation. That is, when 1.5 ≤ At that time, the soil layer was determined to be saline soil that could be considered collapsible under rated pressure. As a collapsibility coefficient, it is used to calculate the collapsibility of the soil layer it represents; when 1.5 > At that time, the soil layer was determined to be saline soil that could be considered as collapsible under rated pressure. The solution coefficient is used to calculate the amount of solution in the soil layer it represents.

[0037] In specific implementation, in step five, when the undisturbed soil sample is saline soil exhibiting collapsibility and solution collapse under rated pressure, the saline soil is classified into collapsibility-dominated saline soil and solution-dominated saline soil according to the degree to which collapsibility and solution collapse dominate the settlement deformation. That is, when 1.5 ≤ At that time, the soil layer was determined to be saline soil dominated by collapsibility under rated pressure. As a collapsibility coefficient, it is used to calculate the collapsibility of the soil layer it represents; when 1.5 > At that time, the soil layer was determined to be saline soil dominated by dissolution under rated pressure. The solution coefficient is used to calculate the amount of solution in the soil layer it represents.

[0038] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for quantitatively distinguishing between wet collapse and solution collapse of collapsible soil under rated pressure, characterized in that, The method includes the following steps: Step 1: Sampling and Preparation of Uncircular Soil Samples: Take one undisturbed soil sample from the soil layer to be evaluated and prepare two samples with a height of [missing information]. The undisturbed soil samples from the ring cutter, namely the first undisturbed soil sample from the ring cutter and the second undisturbed soil sample from the ring cutter. Step 2: Immersion Consolidation Test with Different Solutions: Using distilled water as the solution, an immersion consolidation test was conducted on the undisturbed soil sample of the first ring cutter under the rated pressure P. The stable settling height of the undisturbed soil sample of the first ring cutter under the rated pressure P was obtained. ; Using saturated NaCl solution as the solution, a consolidation test was conducted on the undisturbed soil sample of the second ring cutter under the rated pressure P by immersion in saturated NaCl solution. The stable settling height of the undisturbed soil sample of the second ring cutter under the rated pressure P was obtained. ; Step 3: Calculate the additional settlement per unit thickness of the undisturbed soil sample under rated pressure. The process is as follows: Using the formula... The additional settlement per unit thickness of the first ring cutter undisturbed soil sample using distilled water as the solution was calculated under rated pressure. ,in, The settling stability height of the undisturbed soil sample under rated pressure P is the height of the ring cutter under water immersion. Using formula The additional settlement per unit thickness of the second ring cutter undisturbed soil sample using saturated NaCl solution as the solution was calculated under rated pressure. ; Step 4: Quantitatively calculate the amount of solution collapse per unit thickness of the undisturbed soil sample under rated pressure using the difference method: Using the formula... The amount of solution collapse per unit thickness of the undisturbed soil sample under rated pressure was calculated. ; Step 5: Determining the dominance of wet collapse and solution collapse under rated pressure, the process is as follows: when <0.01 and If the value is ≥0.015, the soil layer is determined to be collapsible saline soil under rated pressure. As a collapsibility coefficient, it is used to calculate the collapsibility of the soil layer it represents; when <0.005, 0.01≤ <0.015 and If the value is ≥0.015, the soil layer is determined to be saline soil that can be considered as collapsible under rated pressure. As a collapsibility coefficient, it is used to calculate the collapsibility of the soil layer it represents; When 0.005≤ <0.01, <0.01 and 0.01≤ If the value is less than 0.015, the soil layer is determined to be saline soil that can be considered as collapsible under rated pressure. As a solution collapse coefficient, the amount of solution collapse of the soil layer it represents is calculated. when ≥0.01、 If the value is less than 0.015, the soil layer is determined to be saline soil with collapsibility under rated pressure. As a solution collapse coefficient, the amount of solution collapse of the soil layer it represents is calculated. When 0.005≤ <0.01, 0.005< <0.015, and 0.015≤ When <0.025, the soil layer is determined to be saline soil that can be considered as collapsible and soluble under rated pressure; when ≥0.01、 When the value is ≥0.015, the soil layer is determined to be saline soil with collapsibility and solubility under rated pressure; when <0.01, <0.01, and If the value is less than 0.01, the soil layer is determined to be saline soil that does not exhibit collapsibility or solubility under rated pressure, and is classified as ordinary saline soil. It is used as a deformation coefficient to calculate the deformation of the soil layer it represents; In step five, when the undisturbed soil sample is saline soil that can be considered as collapsible and soluble under rated pressure, the saline soil is classified into saline soil that can be considered as collapsible and saline soil that can be considered as soluble based on the degree to which collapsibility and soluble collapse dominate the settlement deformation. That is, when 1.5 ≤ At that time, the soil layer was determined to be saline soil that could be considered collapsible under rated pressure. As a collapsibility coefficient, it is used to calculate the collapsibility of the soil layer it represents; when 1.5 > At that time, the soil layer was determined to be saline soil that could be considered as collapsible under rated pressure. As a solution collapse coefficient, the amount of solution collapse of the soil layer it represents is calculated. In step five, when the undisturbed soil sample is saline soil exhibiting collapsibility and solution collapse under rated pressure, the saline soil is classified into collapsibility-dominated saline soil and solution-dominated saline soil based on the degree to which collapsibility and solution collapse dominate the settlement deformation. Specifically, when 1.5... ≤ At that time, the soil layer was determined to be saline soil dominated by collapsibility under rated pressure. As a collapsibility coefficient, it is used to calculate the collapsibility of the soil layer it represents; when 1.5 > At that time, the soil layer was determined to be saline soil dominated by dissolution under rated pressure. The solution coefficient is used to calculate the amount of solution in the soil layer it represents.

2. The method for quantitatively distinguishing between wet collapse and solution collapse of collapsible soil under rated pressure according to claim 1, characterized in that: In step two, the process of conducting immersion consolidation tests on the undisturbed soil samples from the first and second ring cutters is as follows: Step 201: Level the consolidation apparatus and simultaneously move the dial indicator head to ensure that the dial indicator pointer and measuring rod can rotate freely. Step 202: For the two ring cutter undisturbed soil samples, first place them at the bottom of the consolidation container in the following order: protective ring (1), lower permeable stone (2), first thin filter paper (3), ring cutter undisturbed soil sample (4), guide ring (5), second thin filter paper (6), upper permeable stone (7), and pressure cover plate. Place the consolidation container on the consolidation apparatus platform, and attach the bottom of the crossbeam of the consolidation apparatus to the top of the pressure cover plate. Install a dial gauge at the center of the crossbeam. Step 203: Apply a pre-pressure of 1 kPa to make the two undisturbed soil samples of the ring cutter fully contact their corresponding first bottom permeable stone and first top permeable stone, and adjust the dial gauges corresponding to the two undisturbed soil samples of the ring cutter to the initial reading. Step 204: After pressurizing the two undisturbed soil samples with ring cutters to the rated pressure, read the deformation reading of each undisturbed soil sample with ring cutters every 30 minutes until the deformation of the two undisturbed soil samples with ring cutters is stable. Step 205: Inject distilled water into the water tank where the first ring cutter undisturbed soil sample is located, and inject distilled water up to the height of the top surface of the permeable stone until the deformation of the first ring cutter undisturbed soil sample stabilizes. Saturated NaCl solution was injected into the water tank where the second ring cutter undisturbed soil sample was located, and the saturated NaCl solution was injected up to the height of the top permeable stone until the deformation of the second ring cutter undisturbed soil sample stabilized. Step 206: After the immersion consolidation test is completed, remove the first and second ring cutter undisturbed soil samples.

3. The method for quantitatively distinguishing between wet collapse and solution collapse of collapsible soil under rated pressure according to claim 2, characterized in that: In step 205, before the deformation of the undisturbed soil sample of the first ring cutter stabilizes, distillation is promptly added to the water tank where the undisturbed soil sample of the first ring cutter is located, so that the water head in the water tank where the undisturbed soil sample of the first ring cutter is located is the same as that at the top of the permeable stone. Before the deformation of the undisturbed soil sample of the second ring cutter stabilizes, saturated NaCl solution should be added to the water tank containing the undisturbed soil sample of the second ring cutter in a timely manner, so that the water head in the water tank containing the undisturbed soil sample of the second ring cutter is the same as that at the top of the permeable stone.

4. The method for quantitatively distinguishing between wet collapse and solution collapse of collapsible soil under rated pressure according to claim 2, characterized in that: In step 205, before the deformation of the first ring cutter undisturbed soil sample stabilizes, the distilled water in the water tank containing the first ring cutter undisturbed soil sample is replaced at set intervals. At the same time, before the deformation of the second ring cutter undisturbed soil sample stabilizes, the saturated NaCl solution in the water tank containing the second ring cutter undisturbed soil sample is replaced at set intervals.

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