Indoor consolidation test method and device for loess collapsibility coefficient in humidifying process

Abstract

The invention belongs to the technical field of loess collapsibility coefficient measurement, and provides a loess collapsibility coefficient indoor consolidation test method and a loess collapsibility coefficient indoor consolidation test device in a humidifying process, after water injection, the infiltration rate is obtained according to the water volume change starting time of the upper end, the middle and the lower end of a soil sample, and the loess collapsibility coefficient is measured according to the infiltration rate and the water difference of the upper end and the lower end of the soil sample. Whether the water is fully distributed in the soil sample is judged, so that the problem that the water is not fully distributed in the soil sample for loading and calculation to increase errors is avoided; moreover, when moisture is fully distributed in the soil sample, after the soil sample is pressurized to the initial soil pressure value, a vertical load is applied to the soil sample, and the pressure of upper soil on the soil sample in an actual environment is considered and simulated, so that the error between indoor consolidation test data and outdoor water immersion test data is further reduced; therefore, on the basis of ensuring the accuracy, the purpose of measuring the collapsibility coefficient of the soil body with multiple groups of water contents in the humidifying process through an indoor consolidation test is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of loess collapsibility coefficient measurement, and in particular relates to an indoor consolidation test method and device for loess collapsibility coefficient during a humidification process. Background Art

[0002] At present, there are two main test methods for measuring the loess collapsibility coefficient: indoor consolidation and outdoor immersion. The indoor consolidation test is to saturate the original loess or reshaped loess with different moisture contents and then conduct a consolidation test. After the deformation of the sample stabilizes, the soil collapsibility coefficient is calculated; the outdoor immersion test is to select a test site outdoors, arrange settlement standards according to relevant specifications, and then conduct immersion for 2-3 months. After the test is completed, the soil collapsibility curve is drawn to calculate the soil collapsibility coefficient of the entire layer or each layer.

[0003] Outdoor immersion tests can comprehensively and accurately determine the collapsibility of soil during wetting, but they are expensive and time-consuming. Indoor consolidation tests are relatively quick, simple, and economical. However, due to the limitations of the experimental equipment, they can only measure the collapsibility of soil with one moisture content at a time, and cannot measure the collapsibility of soil during wetting. The data obtained differs significantly from those of outdoor immersion tests. Specifically, the main reasons why indoor consolidation tests can only measure the collapsibility of soil with one moisture content, and why the measured data differ significantly from the actual data of outdoor immersion tests, are: first, the soil sample is subjected to pressure from the upper soil layer in the actual environment. If the pressure of the upper soil layer is not taken into account, the indoor consolidation test data will have a large error compared to the outdoor immersion test data. Second, the infiltration rate of water in the soil sample and the distribution of water in the soil sample cannot be determined. For example, if the water is not fully distributed in the soil sample at a certain stage and loading and calculation are performed, it will lead to large errors. Summary of the Invention

[0004] In order to solve the above problems, the present invention proposes an indoor consolidation test method and device for the loess collapsibility coefficient during humidification. After water injection, the infiltration rate is obtained according to the time when the water amount at the upper, middle and lower ends of the soil sample starts to change, and the infiltration rate and the moisture difference between the upper and lower ends of the soil sample are used to judge whether the moisture is fully distributed in the soil sample, thereby avoiding the problem of increased errors in loading and calculation caused by insufficient distribution of moisture in the soil sample. Moreover, when the moisture is fully distributed in the soil sample, the soil sample is pressurized to the initial soil pressure value, and then a vertical load is applied to the soil sample. The pressure on the soil sample itself from the upper soil in the actual environment is taken into consideration and simulated, thereby further reducing the error between the indoor consolidation test data and the outdoor immersion test data. Therefore, the purpose of measuring the collapsibility coefficient of multiple groups of soil bodies with moisture contents during humidification through indoor consolidation tests is achieved on the basis of ensuring accuracy.

[0005] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0006] In a first aspect, the present invention provides an indoor consolidation test method for loess collapsibility during a humidification process, comprising:

[0007] Obtain the sampling depth, natural moisture content and saturated moisture content of soil samples;

[0008] obtaining an initial soil pressure value of the soil sample according to the sampling depth; setting a plurality of intermediate target moisture contents according to the natural moisture content and the saturated moisture content; obtaining a required water volume according to a first target moisture content among the plurality of intermediate target moisture contents; and injecting water into the soil sample according to the required water volume;

[0009] After water injection, the time when the water volume at the top, middle, and bottom of the soil sample begins to change is obtained; based on the time when the water volume at the top, middle, and bottom of the soil sample begins to change, the infiltration rate is obtained; based on the infiltration rate and the water content difference between the top and bottom of the soil sample, it is determined whether the water is fully distributed in the soil sample;

[0010] When the moisture is fully distributed in the soil sample, the soil sample is pressurized to the initial soil pressure value, and then a vertical load is applied to the soil sample; when the loading displacement does not change within a preset time, the collapsibility coefficient of the soil sample at the first target moisture content is determined by the ratio of the loading displacement to the initial height of the soil sample;

[0011] The process of determining the required amount of water, judging whether the water is fully distributed in the soil sample, and loading is repeated to obtain the collapsibility coefficient of the soil sample at all other intermediate target moisture contents.

[0012] Furthermore, the initial soil pressure value is equal to the product of soil weight and sampling depth.

[0013] Furthermore, the amount of water required for the first target moisture content is equal to the ratio of the difference between the first target moisture content and the natural moisture content multiplied by the dry soil mass to the density of water; the amount of water required for other target moisture contents is equal to the ratio of the difference between the current target moisture content and the previous target moisture content multiplied by the dry soil mass to the density of water.

[0014] Furthermore, the infiltration rate v is:

[0015]

[0016] Among them, t u The time when the water content at the upper end of the soil sample begins to change; t m The time when the water content in the middle of the soil sample begins to change; t d The time when the water volume at the lower end of the soil sample begins to change; h1 is the distance between the upper end and the middle position of the soil sample; h2 is the distance between the middle position and the lower end of the soil sample.

[0017] Furthermore, the soil collapsibility coefficient δ under the nth target moisture content is nfor:

[0018]

[0019] in, is the total shrinkage of the soil sample after n loadings; H1 is the initial height of the soil sample.

[0020] Furthermore, when the moisture difference between the upper and lower ends reaches a preset value and the infiltration rate is less than a preset rate, it is determined that the injected water has been fully distributed in the soil.

[0021] In a second aspect, the present invention further provides an indoor consolidation test device for loess collapsibility during a humidification process, comprising a bracket, a base disposed on the bracket, a chamber, a first permeable stone, a second permeable stone, a pressure plate, a water injection hole, a loading rod, and a pressure cylinder, and a first moisture sensor, a second moisture sensor, and a third moisture sensor disposed at the upper end, middle end, and lower end of the soil sample, respectively;

[0022] The loading rod is provided with a displacement meter, the bottom of the loading rod is a pressure plate, and the water injection hole is provided on the pressure plate; the displacement meter, the first moisture sensor, the second moisture sensor, the third moisture sensor and the pressurized cylinder are all connected to a controller; the controller is configured as follows:

[0023] The initial soil pressure value of the soil sample is obtained according to the sampling depth; multiple intermediate target moisture contents are set according to the natural moisture content and saturated moisture content of the soil sample; the required water volume is obtained according to the first target moisture content among the multiple intermediate target moisture contents; and water is injected into the soil sample according to the required water volume;

[0024] After water injection, the time when the water volume at the top, middle, and bottom of the soil sample begins to change is obtained; based on the time when the water volume at the top, middle, and bottom of the soil sample begins to change, the infiltration rate is obtained; based on the infiltration rate and the water content difference between the top and bottom of the soil sample, it is determined whether the water is fully distributed in the soil sample;

[0025] When the moisture is fully distributed in the soil sample, the soil sample is pressurized to the initial soil pressure value, and then a vertical load is applied to the soil sample; when the loading displacement does not change within a preset time, the collapsibility coefficient of the soil sample at the first target moisture content is determined by the ratio of the loading displacement to the initial height of the soil sample;

[0026] The process of determining the required amount of water, judging whether the water is fully distributed in the soil sample, and loading is repeated to obtain the collapsibility coefficient of the soil sample at all other intermediate target moisture contents.

[0027] Furthermore, the first permeable stone and the second permeable stone are located in the chamber and are respectively located at two ends of the soil sample.

[0028] Furthermore, a circular groove is provided on the top of the base.

[0029] Furthermore, the lower side of the displacement meter contacts the bracket.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The present invention first obtains the initial earth pressure value of the soil sample according to the sampling depth; sets multiple intermediate target water contents according to the natural water content and the saturated water content; obtains the required water volume according to the first target water content among the multiple intermediate target water contents; and injects water into the soil sample according to the required water volume; after water injection, obtains the time when the water volume at the upper end, middle end and lower end of the soil sample starts to change; obtains the infiltration rate according to the time when the water volume at the upper end, middle end and lower end of the soil sample starts to change; judges whether the water is fully distributed in the soil sample according to the infiltration rate and the water difference between the upper end and the lower end of the soil sample; then, when the water is fully distributed in the soil sample, pressurizes the soil sample to the initial earth pressure value, and then applies a vertical load to the soil sample; when the loading displacement does not change within a preset time, determines the collapsibility coefficient of the soil sample at the first target water content by the ratio of the loading displacement to the initial height of the soil sample; finally, repeats the process of determining the required water volume, judging whether the water is fully distributed in the soil sample, and the loading process to obtain the collapsibility coefficient of the soil sample at all other intermediate target water contents. After water injection, the infiltration rate is obtained according to the time when the water volume at the upper, middle and lower ends of the soil sample begins to change, and the infiltration rate and the moisture difference between the upper and lower ends of the soil sample are used to judge whether the moisture is fully distributed in the soil sample, thereby avoiding the problem of increased errors in loading and calculation caused by moisture not being fully distributed in the soil sample; and, when the moisture is fully distributed in the soil sample, the soil sample is pressurized to the initial soil pressure value, and then a vertical load is applied to the soil sample, which takes into account and simulates the pressure of the upper soil on the soil sample itself in the actual environment, further reducing the error between the indoor consolidation test data and the outdoor immersion test data; therefore, the purpose of determining the wetting coefficient of multiple groups of soil bodies with moisture content during the humidification process through indoor consolidation tests is achieved on the basis of ensuring accuracy.

[0032] When measuring the collapsibility coefficient of loess soil with different moisture contents, the present invention eliminates the need to replace or use different soil samples, resulting in simple operation and accurate data. The collapsibility coefficient during soil humidification can be obtained through indoor testing, more comprehensively and accurately reflecting soil collapsibility characteristics. The present invention can simulate the earth pressure exerted on soil samples in strata, resulting in more accurate data. This data can be obtained by improving an indoor consolidation instrument, making it low-cost and easy to mass-produce. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The drawings constituting a part of the specification of this embodiment are used to provide a further understanding of this embodiment. The schematic embodiments and descriptions of this embodiment are used to explain this embodiment and do not constitute an improper limitation on this embodiment.

[0034] Figure 1 Schematic diagram of the experimental device of Example 1 of the present invention;

[0035] Figure 2 This is a schematic diagram of controller connection according to embodiment 1 of the present invention;

[0036] Figure 3 This is a schematic diagram of a base according to Example 1 of the present invention;

[0037] Figure 4 This is a schematic diagram of controller connection according to embodiment 1 of the present invention;

[0038] Among them, 1. bracket; 101. base; 1011. annular groove; 1012. water inlet pipe; 102. chamber; 103. first permeable stone; 104. second permeable stone; 105. pressure plate; 106. water injection hole; 107. loading rod; 108. pressurized cylinder; 2. displacement meter; 3. first moisture sensor; 4. second moisture sensor; 5. third moisture sensor; 6. soil sample; 7. controller. DETAILED DESCRIPTION

[0039] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0040] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0041] Example 1:

[0042] This embodiment provides an indoor consolidation test method for the loess collapsibility coefficient during humidification, and as shown in the figure, also provides an indoor consolidation test device corresponding to the method; the device includes a bracket 1, and a base 101, a chamber 102, a first permeable stone 103, a second permeable stone 104, a pressure plate 105, a water injection hole 106, a loading rod 107 and a pressurized cylinder 108 arranged on the bracket 1.

[0043] The bracket 1 is the main part of the indoor consolidation test, and the base 101 and the pressurized cylinder 108 are all fixed on the bracket 1. The chamber 102 is set on the base 101, for accommodating the soil sample 6; the first permeable stone 103 and the second permeable stone 104 are located in the chamber 102, and are respectively located at the two ends of the soil sample 6; the water injection hole 106 can be opened in the pressurized plate 105 or other positions, and the water injection hole 106 is connected to other external water supply equipment through the main water pipeline; the pressurized cylinder 108 is provided with an air inlet and an air outlet, etc.; the loading rod 107 can be set to an "I" shape, with the top placed in the pressurized cylinder 108, and can move up and down as the pressure of the pressurized cylinder 108 changes.

[0044] The loading rod 107 is provided with a displacement meter 2, the lower side of which contacts the bracket 1. The bottom of the loading rod 107 is a pressure plate 105, which is provided with a water injection hole 106 for changing the moisture content of the soil. Optionally, the water injection hole 106 is opened during water injection and closed with a piston after water injection.

[0045] A first moisture sensor 3, a second moisture sensor 4, and a third moisture sensor 5 are respectively provided at the top, middle, and bottom of the soil sample 6 to determine whether the soil sample 6 has reached the required moisture content. The first moisture sensor 3, the second moisture sensor 4, and the third moisture sensor 5 can optionally be a moisture monitor, a fiber optic sensor, or other moisture sensor.

[0046] like Figure 2 As shown, the displacement meter 2, the first moisture sensor 3, the second moisture sensor 4, the third moisture sensor 5 and the pressurizing cylinder 108 are all connected to the controller 7; the controller 7 receives the detection data of the displacement meter 2, the first moisture sensor 3, the second moisture sensor 4, and the third moisture sensor 5, and controls the pressurizing cylinder 108 according to the detection data.

[0047] like Figure 3 and Figure 4 As shown, a circular groove is provided on the top of the base 101 to ensure that the water in the water-receiving chamber can penetrate into the soil sample 6 to be tested. In some embodiments, a water inlet pipe 1012 connected to the circular groove 1011 can be provided in the base 101. The water inlet pipe 1012 is connected to an external water supply device as an auxiliary water injection pipeline.

[0048] The consolidation test method in this embodiment includes:

[0049] S1. Determine the sampling depth of soil sample 6 and calculate the initial soil pressure σ on the soil sample based on the sampling depth h:

[0050] σ=γh;

[0051] Wherein, γ is the soil weight, and h is the sampling depth. Optionally, the sampling depth is the depth from the ground to the upper surface of the soil sample 6.

[0052] In some other embodiments, considering the actual environment, the initial earth pressure σ of the soil body is not only mainly affected by the soil layer directly above, but also by the surrounding soil layers. Based on this, the influence of the surrounding soil layers is added to the calculation of the initial earth pressure σ:

[0053] σ=γh+μ;

[0054] Here, μ is the influence of the surrounding soil layers on the initial earth pressure σ, which can be obtained by comparing indoor and outdoor tests. Adding the influence of the surrounding soil layers to the original calculated initial earth pressure σ can further improve the simulation of the actual soil and reduce the error between the indoor consolidation test data and the outdoor immersion test data.

[0055] S2. Test the natural moisture content ω0 and saturated moisture content ω of the soil sample to be tested. sat , set n groups of intermediate moisture content. Test the natural moisture content ω0 and saturated moisture content ω of the soil sample to be tested sat This can be achieved through conventional technology and will not be described in detail here.

[0056] S3. Install the natural soil sample 6 in the ring cutter into the test device, and insert the moisture sensors on both sides of the test device into the soil sample 6 to monitor the moisture content of the soil sample. The ring cutter is a sampling device and will not be described in detail here.

[0057] S4. Calculate the amount of water V1 required for the soil to reach the first target moisture content ω1:

[0058] V1=m s (ω1-ω0) / ρ w ;

[0059] Among them, m s is the dry soil mass, ρ w is the density of water. Then open the water injection hole, inject the calculated required amount of water into the water receiving chamber, and close the water injection hole.

[0060] S5, respectively record the time t when the first moisture sensor 3, the second moisture sensor 4 and the third moisture sensor 5 start to change u , t m and t d , the distance between the first moisture sensor 3 and the second moisture sensor 4 is h1, and the distance between the second moisture sensor 4 and the third moisture sensor 5 is h2, then the infiltration rate v is:

[0061]

[0062] S6. Determine whether the moisture is sufficiently distributed in the soil sample based on the infiltration rate and the moisture difference between the upper and lower ends of the soil sample; when the moisture difference detected by the first moisture sensor 3 and the third moisture sensor 5 reaches a preset value, it can be considered that the injected moisture has been sufficiently distributed in the soil. For example, when the moisture difference detected by the first moisture sensor 3 and the third moisture sensor 5 is 1%, it can be considered that the injected moisture has been sufficiently distributed in the soil.

[0063] In some other embodiments, when the moisture difference monitored by the first moisture sensor 3 and the third moisture sensor 5 reaches a preset value, and the infiltration rate is less than the preset rate, it indicates that the moisture entering the soil sample 6 is saturated or close to saturation, and the injected moisture has been fully distributed in the soil; optionally, the preset rate is the infiltration rate or other set value.

[0064] S7. Inflate the loading cylinder and pressurize the soil to the initial earth pressure, applying a vertical load to the soil. After the loading device pressurizes the soil to the initial earth pressure, the vertical load is applied to the soil sample. This takes into account and simulates the pressure exerted on the soil sample in a real environment by the overlying soil, reducing the error between the indoor consolidation test data and the outdoor immersion test data.

[0065] S8. Wait until the deformation of the soil block is stable, that is, the displacement meter value does not change for a long time, read the displacement meter reading Δh1, which is the soil collapse amount after the first loading. Calculate the soil collapse coefficient δ1 at the first target moisture content according to the following formula:

[0066]

[0067] Among them, H1 is the initial height of the soil sample.

[0068] S9. Calculate the water volume V2 required for the second target moisture content ω2:

[0069] V2=m s (ω2-ω1) / ρ w ;

[0070] The air pressure in the loading cylinder is removed, the loading rod returns to its original position, and steps S4 and S5 are repeated.

[0071] S10. Calculate the soil collapsibility coefficient δ2 under the second target moisture content:

[0072]

[0073] Among them, Δh2 is the shrinkage of the soil sample after the second loading, and Δh1+Δh2 is the total shrinkage of the soil sample after the two loadings.

[0074] S11, repeat steps S3 to S10 until the target moisture content reaches the saturated moisture content, wherein the nth target moisture content ω n Required water volume V n for:

[0075] V n =m s (ω n -ω n-1 ) / ρ w ;

[0076] Soil collapsibility coefficient δ at the nth target moisture content n for:

[0077]

[0078] in, is the total collapsibility of the soil sample after n loadings.

[0079] According to the above method, the infiltration coefficient and collapsibility coefficient of soil samples at different moisture contents can be determined, and the relationship curve between moisture content, infiltration coefficient and collapsibility coefficient can be drawn. This can be used to predict the stability of slopes under different rainfall conditions and provide more accurate constitutive model parameters for slope stability calculation.

[0080] Example 2:

[0081] This embodiment provides an indoor consolidation test device for the loess collapsibility coefficient during humidification, including a bracket 1, and a base 101, a chamber 102, a first permeable stone 103, a second permeable stone 104, a pressure plate 105, a water injection hole 106, a loading rod 107 and a pressure cylinder 108 arranged on the bracket 1.

[0082] The bracket 1 is the main part of the indoor consolidation test, and the base 101 and the pressurized cylinder 108 are all fixed on the bracket 1. The chamber 102 is set on the base 101, for accommodating the soil sample 6; the first permeable stone 103 and the second permeable stone 104 are located in the chamber 102, and are respectively located at the two ends of the soil sample 6; the water injection hole 106 can be opened in the pressurized plate 105 or other positions, and the water injection hole 106 is connected to other external water supply equipment through the main water pipeline; the pressurized cylinder 108 is provided with an air inlet and an air outlet, etc.; the loading rod 107 can be set to an "I" shape, with the top placed in the pressurized cylinder 108, and can move up and down as the pressure of the pressurized cylinder 108 changes.

[0083] The loading rod 107 is provided with a displacement meter 2, the lower side of which contacts the bracket 1. The bottom of the loading rod 107 is a pressure plate 105, which is provided with a water injection hole 106 for changing the moisture content of the soil. Optionally, the water injection hole 106 is opened during water injection and closed with a piston after water injection.

[0084] The upper, middle, and lower ends are respectively provided with a first moisture sensor 3, a second moisture sensor 4, and a third moisture sensor 5 for determining whether the soil sample 6 to be tested has reached the required moisture content. The first moisture sensor 3, the second moisture sensor 4, and the third moisture sensor 5 can optionally be a moisture monitor, an optical fiber sensor, or other moisture sensors.

[0085] like Figure 2 As shown, the displacement meter 2, the first moisture sensor 3, the second moisture sensor 4, the third moisture sensor 5 and the pressurized cylinder 108 are all connected to the controller 7; the controller 7 is configured as follows:

[0086] obtaining an initial soil pressure value of the soil sample according to the sampling depth; setting a plurality of intermediate target moisture contents according to the natural moisture content and the saturated moisture content; obtaining a required water volume according to a first target moisture content among the plurality of intermediate target moisture contents; and injecting water into the soil sample according to the required water volume;

[0087] After water injection, the time when the water volume at the top, middle, and bottom of the soil sample begins to change is obtained; based on the time when the water volume at the top, middle, and bottom of the soil sample begins to change, the infiltration rate is obtained; based on the infiltration rate and the water content difference between the top and bottom of the soil sample, it is determined whether the water is fully distributed in the soil sample;

[0088] When the moisture is fully distributed in the soil sample, the soil sample is pressurized to the initial soil pressure value, and then a vertical load is applied to the soil sample; when the loading displacement does not change within a preset time, the collapsibility coefficient of the soil sample at the first target moisture content is determined by the ratio of the loading displacement to the initial height of the soil sample;

[0089] The process of determining the required amount of water, judging whether the water is fully distributed in the soil sample, and loading is repeated to obtain the collapsibility coefficient of the soil sample at all other intermediate target moisture contents.

[0090] The indoor consolidation test device for loess collapsibility coefficient during humidification in this embodiment also includes other technical features of the test device in Example 1, and all contents of the test method in Example 1 can be executed during the test, which will not be described in detail here.

[0091] The above description is merely a preferred embodiment of this embodiment and is not intended to limit this embodiment. Those skilled in the art will readily appreciate that this embodiment may be modified and varied in various ways. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this embodiment shall be within the scope of protection of this embodiment.

Claims

1. Indoor consolidation test method for loess collapsibility during humidification, characterized in that: include: Obtain the sampling depth, natural moisture content and saturated moisture content of soil samples; Obtaining the initial soil pressure value of the soil sample according to the sampling depth; According to the natural moisture content and the saturated moisture content, a plurality of intermediate target moisture contents are set; according to the first target moisture content among the plurality of intermediate target moisture contents, a required amount of water is obtained; and according to the required amount of water, water is injected into the soil sample; After water injection, the time when the water volume at the upper, middle and lower ends of the soil sample starts to change is obtained; the infiltration rate is obtained according to the time when the water volume at the upper, middle and lower ends of the soil sample starts to change; according to the infiltration rate and the water difference between the upper and lower ends of the soil sample, it is judged whether the water is fully distributed in the soil sample; When the moisture is fully distributed in the soil sample, the soil sample is pressurized to the initial soil pressure value, and then a vertical load is applied to the soil sample; when the loading displacement does not change within a preset time, the collapsibility coefficient of the soil sample under the first target moisture content is determined by the ratio of the loading displacement to the initial height of the soil sample; The process of determining the required amount of water, judging whether the water is fully distributed in the soil sample, and the loading process are repeated to obtain the collapsibility coefficient of the soil sample at all other intermediate target moisture contents.

2. The indoor consolidation test method for loess collapsibility during humidification according to claim 1, characterized in that: The initial soil pressure value is equal to the product of soil weight and sampling depth.

3. The indoor consolidation test method for loess collapsibility during humidification process according to claim 1, characterized in that: The amount of water required for the first target moisture content is equal to the ratio of the difference between the first target moisture content and the natural moisture content multiplied by the dry soil mass to the density of water; the amount of water required for other target moisture contents is equal to the ratio of the difference between the current target moisture content and the previous target moisture content multiplied by the dry soil mass to the density of water.

4. The indoor consolidation test method for loess collapsibility during humidification according to claim 1, characterized in that: Then the infiltration rate v is: Among them, t u The time when the water volume at the upper end of the soil sample begins to change; t m The time when the water content in the middle of the soil sample begins to change; t d The time when the water volume at the lower end of the soil sample begins to change; h1 is the distance between the upper end and the middle position of the soil sample; h2 is the distance between the middle position and the lower end of the soil sample.

5. The indoor consolidation test method for loess collapsibility during humidification process according to claim 1, characterized in that: Soil collapsibility coefficient δ at the nth target moisture content n for: in, is the total shrinkage of the soil sample after n loadings; H1 is the initial height of the soil sample.

6. The indoor consolidation test method for loess collapsibility during humidification process according to claim 1, characterized in that: When the moisture difference between the upper and lower positions reaches the preset value and the infiltration rate is less than the preset rate, it is judged that the injected water has been fully distributed in the soil.

7. Indoor consolidation test device for loess collapsibility coefficient during humidification, characterized in that: It includes a bracket, a base arranged on the bracket, a chamber, a first permeable stone, a second permeable stone, a pressure plate, a water injection hole, a loading rod and a pressure cylinder, and a first moisture sensor, a second moisture sensor and a third moisture sensor respectively arranged at the upper end, the middle end and the lower end of the soil sample; The loading rod is provided with a displacement meter, the bottom of the loading rod is a pressure plate, and the water injection hole is provided on the pressure plate; the displacement meter, the first moisture sensor, the second moisture sensor, the third moisture sensor and the pressurized cylinder are all connected to a controller; the controller is configured as follows: The initial soil pressure value of the soil sample is obtained according to the sampling depth; multiple intermediate target moisture contents are set according to the natural moisture content and saturated moisture content of the soil sample; the required water volume is obtained according to the first target moisture content among the multiple intermediate target moisture contents; and water is injected into the soil sample according to the required water volume; After water injection, the time when the water volume at the upper, middle and lower ends of the soil sample starts to change is obtained; the infiltration rate is obtained according to the time when the water volume at the upper, middle and lower ends of the soil sample starts to change; according to the infiltration rate and the water difference between the upper and lower ends of the soil sample, it is judged whether the water is fully distributed in the soil sample; When the moisture is fully distributed in the soil sample, the soil sample is pressurized to the initial soil pressure value, and then a vertical load is applied to the soil sample; when the loading displacement does not change within a preset time, the collapsibility coefficient of the soil sample under the first target moisture content is determined by the ratio of the loading displacement to the initial height of the soil sample; The process of determining the required amount of water, judging whether the water is fully distributed in the soil sample, and the loading process are repeated to obtain the collapsibility coefficient of the soil sample at all other intermediate target moisture contents.

8. The indoor consolidation test device for loess collapsibility coefficient during humidification as claimed in claim 7, characterized in that: The first permeable stone and the second permeable stone are located in the chamber and are respectively located at two ends of the soil sample.

9. The indoor consolidation test device for loess collapsibility coefficient during humidification process as claimed in claim 7, characterized in that: A circular groove is arranged on the top of the base.

10. The indoor consolidation test device for loess collapsibility coefficient during humidification process as claimed in claim 7, characterized in that: The lower side of the displacement meter is in contact with the bracket.

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