A test method for obtaining soil compression modulus using expansive concrete

Abstract

The present invention discloses a test method for obtaining soil compression modulus using expansive concrete, which relates to the field of soil testing technology. The method comprises: excavating a set number of test pits of a set size at a project site, pouring expansive concrete containing different set amounts of expansive agent in each test pit; during the solidification process of the expansive concrete, obtaining the maximum test pressure value at multiple test points on the sidewall of each test pit, and obtaining the volume of the expansive concrete after the expansive concrete is completely solidified; and obtaining the soil compression modulus based on the maximum test pressure value at each test point on the sidewall of each test pit and the volume of the expansive concrete after complete solidification. This method solves the problem in the prior art that the soil is disturbed during the process of collecting soil samples from the project construction site and re-preparing soil samples in the laboratory, which affects the accuracy of the test results.

Description

Technical Field

[0001] The present invention relates to the technical field of soil testing, and in particular to a testing method for obtaining soil compression modulus by utilizing expansive concrete. Background Art

[0002] The compression modulus is an important indicator for determining soil compressibility and calculating foundation compression deformation. The smaller the soil's compression modulus, the higher its compressibility. Because soil is compressible, the impact of the stress distribution in the foundation soil under the action of upper loads on the soil's compression process must be considered when calculating foundation settlement. Therefore, soil compressibility is crucial for calculating foundation settlement.

[0003] In the existing technology, the compression modulus of soil is generally obtained through indoor consolidation tests. This requires collecting soil samples from the project construction site and then re-preparing the soil samples in the laboratory. During this process, the soil is disturbed, which affects the accuracy of the test results. Summary of the Invention

[0004] In response to the defects existing in the prior art, the purpose of the present invention is to provide a test method for obtaining the compression modulus of soil using expansive concrete, which can solve the problem in the prior art that after collecting soil samples from the project construction site, the soil is disturbed during the process of re-preparing the soil samples in the laboratory, resulting in a loss of accuracy of the test results.

[0005] In order to achieve the above purpose, the technical solution adopted by the present invention is:

[0006] This program provides a test method for obtaining the compression modulus of soil using expansive concrete, including:

[0007] Excavate a set number of test pits of a set size at the project site, and pour expansive concrete containing different set amounts of expansive agent into each test pit;

[0008] During the solidification process of the expansive concrete, the maximum test pressure value at multiple test points on the side wall of each test pit is obtained, and the volume of the expansive concrete after the expansive concrete is completely solidified is obtained;

[0009] The soil compression modulus was obtained based on the maximum test pressure value at each test point on the side wall of each test pit and the volume of the expansive concrete after complete solidification.

[0010] In some optional solutions, obtaining the soil compression modulus based on the maximum test pressure value at each test point on the side wall of each test pit and the volume of the fully solidified expansive concrete includes:

[0011] According to the maximum test pressure value of each test point on the side wall of each test pit, the average pressure on the soil of each test pit is obtained;

[0012] The compression modulus of the soil is obtained based on the average pressure on the soil and the volume of the expanded concrete after complete solidification.

[0013] In some optional solutions, the test pit is a rectangular parallelepiped, and the detection points are arranged at the upper, middle and lower parts of the middle positions of the four sides of the test pit, with a total of twelve detection points.

[0014] In some alternative solutions, according to the formula:

[0015]

[0016] Obtain the average pressure on the soil in each test pit;

[0017] in, is the average pressure on the soil of the i-th test pit, i = 1~n, n is the number of measurement moments, P lt is the pressure value of the upper left measuring point, P lm is the pressure value of the left middle measuring point, P lb is the pressure value of the lower left measuring point, P rt is the pressure value of the upper right measuring point, P rm is the pressure value of the right middle measuring point, P rb is the pressure value of the lower right measuring point, P ft is the pressure value of the upper front measuring point, P fm is the pressure value of the front middle measuring point, P fb is the pressure value of the front lower measuring point, P bt is the pressure value of the upper rear measuring point, P bm is the pressure value of the rear middle measuring point, P bb is the pressure value of the lower measuring point.

[0018] In some alternative solutions, according to the formula:

[0019] V d =3B×3B×BB 3 =8B 3 , ΔV i =V i -B 3

[0020]

[0021]

[0022]

[0023]

[0024] Obtain soil compression modulus;

[0025] Among them, Vd is the volume of soil within the influence range of expansive concrete, ΔV i is the volume expansion of the expansive concrete in the i-th test pit, V v0 is the sum of the volumes of liquid and gas in the initial state of the soil, V s0 is the solid volume of the soil in the initial state, V vi is the sum of the volumes of liquid and gas in the compressed soil of the i-th test pit, e0 is the initial porosity of the soil, e i is the soil porosity ratio of the i-th test pit, E s is the soil compression modulus, a v is the compression factor.

[0026] In some optional solutions, a pressure sensor is arranged at each detection point to obtain a detection pressure value.

[0027] In some optional solutions, obtaining the volume of the expansive concrete after the expansive concrete is completely solidified includes:

[0028] After the expansive concrete is completely solidified, remove the expansive concrete from the test pit;

[0029] The volume of expansive concrete was obtained by wax sealing method.

[0030] In some optional solutions, before pouring the expansive concrete containing a set amount of expansive agent in the test pit, a concrete cushion layer of a set thickness is poured at the bottom of the test pit.

[0031] In some optional solutions, lubricating oil is applied to the surface of the concrete cushion layer after the concrete cushion layer is completely solidified.

[0032] In some optional solutions, after pouring expansive concrete containing a set amount of expansive agent in the test pit, a ballast load is applied to the top of the test pit.

[0033] Compared with existing technologies, the advantages of the present invention are as follows: This solution excavates a set number of test pits of a set size at the project site, and pours expansive concrete containing different set amounts of expansive agent into each test pit. During the solidification process of the expansive concrete, the maximum test pressure value at multiple test points on the side walls of each test pit is obtained, and the volume of the expansive concrete after complete solidification is obtained. The soil compression modulus is obtained based on the maximum test pressure value at each test point on the side walls of each test pit and the volume of the expansive concrete after complete solidification. This solves the problem in existing technologies that requires soil samples to be collected from the project construction site and then re-prepared in the laboratory, which disturbs the soil and affects the accuracy of the test results. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0035] Figure 1 Schematic diagram of a flow chart of a test method for obtaining soil compression modulus using expansive concrete in an embodiment of the present invention;

[0036] Figure 2 A schematic cross-sectional view of a test pit in an embodiment of the present invention;

[0037] In the figure: 1. Test pit; 2. Inspection point; 3. Concrete cushion; 4. Ballast. DETAILED DESCRIPTION

[0038] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0039] The embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

[0040] like Figure 1 As shown, the present invention provides a test method for obtaining the compression modulus of soil using expansive concrete, comprising:

[0041] S1: Excavate a set number of test pits of a set size at the project site, and pour expansive concrete containing different set amounts of expansive agent into each test pit.

[0042] In this embodiment, the dosage refers to the mass ratio of expansive agent to cement in the expansive concrete. Expansive concrete with different dosages of expansive agent will have different expansion volumes after solidification in each test pit, and will also exert different pressures on the soil on the sidewalls of the test pit.

[0043] S2: During the solidification process of the expansive concrete, the maximum test pressure values ​​at multiple test points on the side wall of each test pit are obtained, and the volume of the expansive concrete after the expansive concrete is completely solidified is obtained.

[0044] S3: Obtain the soil compression modulus based on the maximum test pressure value at each test point on the side wall of each test pit and the volume of the expansive concrete after complete solidification.

[0045] Step S3 specifically includes:

[0046] S31: Obtain the average pressure on the soil of each test pit according to the maximum detection pressure value of each detection point on the side wall of each test pit.

[0047] S32: Obtain the compression modulus of the soil based on the average pressure on the soil and the volume of the expansive concrete after complete solidification.

[0048] like Figure 2 As shown, in some optional embodiments, the test pit 1 is a rectangular parallelepiped, and the detection points 2 are arranged at the upper, middle and lower parts of the middle positions of the four sides of the test pit 1, with a total of twelve detection points.

[0049] In some optional embodiments, according to the formula:

[0050]

[0051] Obtain the average pressure on the soil in each test pit;

[0052] in, is the average pressure on the soil of the i-th test pit, i = 1~n, n is the number of measurement moments, P lt is the pressure value of the upper left measuring point, P lm is the pressure value of the left middle measuring point, P lb is the pressure value of the lower left measuring point, P rt is the pressure value of the upper right measuring point, P rm is the pressure value of the right middle measuring point, P rb is the pressure value of the lower right measuring point, P ft is the pressure value of the upper front measuring point, P fm is the pressure value of the front middle measuring point, P fb is the pressure value of the front lower measuring point, P bt is the pressure value of the upper rear measuring point, P bm is the pressure value of the rear middle measuring point, P bb is the pressure value of the lower measuring point.

[0053] In some optional embodiments, according to the formula:

[0054] V d =3B×3B×BB 3 =8B 3 , ΔV i =V i -B 3

[0055]

[0056]

[0057]

[0058]

[0059] Obtain soil compression modulus;

[0060] Among them, V d is the volume of soil within the influence range of expansive concrete, ΔV i is the volume expansion of the expansive concrete in the i-th test pit, V v0 is the sum of the volumes of liquid and gas in the initial state of the soil, V s0 is the solid volume of the soil in the initial state, V vi is the sum of the volumes of liquid and gas in the compressed soil of the i-th test pit, e0 is the initial porosity of the soil, e i is the soil porosity ratio of the i-th test pit, E s is the soil compression modulus, a v is the compression factor.

[0061] In this embodiment, the test pit is a cube with equal length, width and height, which is convenient for measurement and calculation.

[0062] In some optional embodiments, a pressure sensor is arranged at each detection point to obtain a detection pressure value.

[0063] In some optional embodiments, obtaining the volume of the expansive concrete after the expansive concrete is completely solidified includes:

[0064] After the expansive concrete is completely solidified, remove the expansive concrete from the test pit;

[0065] The volume of expansive concrete was obtained by wax sealing method.

[0066] like Figure 2 As shown, in some optional embodiments, before pouring the expansive concrete containing a set amount of expansive agent in the test pit 1 , a concrete cushion layer 3 of a set thickness is poured at the bottom of the test pit 1 .

[0067] In this embodiment, a concrete cushion layer 3 of a set thickness is poured at the bottom of the test pit to prevent the expansive concrete from expanding and deforming downward.

[0068] In some optional embodiments, after the concrete cushion layer 3 is completely solidified, lubricating oil is applied to the surface of the concrete cushion layer 3 .

[0069] In this embodiment, lubricating oil is applied to the surface of the concrete cushion layer 3 to facilitate separation of the expansive concrete from the concrete cushion layer 3 .

[0070] In some optional embodiments, after pouring expansive concrete containing a set amount of expansive agent in the test pit 1 , a ballast 4 is applied to the top of the test pit 1 .

[0071] In this embodiment, after pouring expansive concrete containing a set amount of expansive agent in the test pit 1, a ballast 4 is applied to the top of the test pit 1 to limit the deformation of the expansive concrete in the vertical direction.

[0072] In some optional embodiments, the expansive agent is a calcium sulfoaluminate concrete expansive agent.

[0073] In summary, this solution involves excavating a set number of test pits of a set size at the project site, and pouring expansive concrete containing different set amounts of expansive agents in each test pit; during the solidification process of the expansive concrete, the maximum test pressure values ​​of multiple test points on the side walls of each test pit are obtained, and the volume of the expansive concrete after it is completely solidified is obtained; based on the maximum test pressure values ​​of each test point on the side walls of each test pit and the volume of the expansive concrete after it is completely solidified, the compression modulus of the soil is obtained. This solves the problem in the prior art that the soil is disturbed during the process of collecting soil samples from the project construction site and then re-preparing soil samples in the laboratory, which affects the accuracy of the test results. The test method provided by the present invention is simple to operate, occupies a small area of ​​the test site, and can be applied to various types of sites such as flat land, valleys, hillsides, and undulating ground.

[0074] The following examples are provided to facilitate understanding of the present invention.

[0075] At a project site, five test pits measuring 20 cm x 20 cm x 25 cm were excavated. A 5 cm thick concrete cushion was poured at the bottom of the pits. After the concrete cushion was completely solidified, a layer of lubricating oil was applied to the surface. Expansive concrete with different expansive agent concentrations of 5%, 10%, 15%, 20%, and 25% was poured into each of the five test pits. A 0.5 ton weight was used as ballast on the top of the test pits. The volume of fully solidified expansive concrete in the five test pits and the maximum test pressure at each test point were calculated. The data are shown in Tables 1-6. In Table 6, the compression modulus corresponding to test pit No. 2 refers to the soil compression modulus with a pressure between 9.83 kPa and 23.67 kPa, the compression modulus corresponding to test pit No. 3 refers to the soil compression modulus with a pressure between 23.67 kPa and 42.33 kPa, the compression modulus corresponding to test pit No. 4 refers to the soil compression modulus with a pressure between 42.33 kPa and 96.54 kPa, and the compression modulus corresponding to test pit No. 5 refers to the soil compression modulus with a pressure between 96.54 kPa and 133.66 kPa.

[0076] Table 1

[0077]

[0078] Table 2

[0079]

[0080]

[0081] Table 3

[0082]

[0083] Table 4

[0084]

[0085] Table 5

[0086]

[0087] Table 6

[0088]

[0089] In the description of this application, it should be noted that the terms "upper" and "lower" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0090] It should be noted that, in this application, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0091] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A test method for obtaining soil compression modulus using expansive concrete, characterized in that: include: Excavate a set number of test pits of a set size at the project site, and pour expansive concrete containing different set amounts of expansive agent into each test pit; During the solidification process of the expansive concrete, the maximum test pressure value at multiple test points on the side wall of each test pit is obtained, and the volume of the expansive concrete after the expansive concrete is completely solidified is obtained; The soil compression modulus is obtained based on the maximum test pressure value at each test point on the side wall of each test pit and the volume of the expansive concrete after complete solidification; The method of obtaining the soil compression modulus based on the maximum test pressure value at each test point on the side wall of each test pit and the volume of the fully solidified expansive concrete includes: According to the maximum test pressure value of each test point on the side wall of each test pit, the average pressure on the soil of each test pit is obtained; The compression modulus of the soil is obtained based on the average pressure on the soil and the volume of the expanded concrete after complete solidification; The test pit is a rectangular parallelepiped, and the detection points are arranged at the upper, middle and lower parts of the middle positions of the four sides of the test pit, with a total of twelve detection points; According to the formula: Obtain the average pressure on the soil in each test pit; in, is the average pressure on the soil of the i-th test pit, i=1~n, n is the number of measurement moments, is the pressure value of the upper left measuring point, is the pressure value of the left middle measuring point, is the pressure value of the lower left measuring point, is the pressure value of the upper right measuring point, is the pressure value of the right middle measuring point, is the pressure value of the lower right measuring point, is the pressure value of the upper front measuring point, is the pressure value of the front-middle measuring point, is the pressure value of the front lower measuring point, is the pressure value of the upper rear measuring point, is the pressure value of the rear middle measuring point, is the pressure value of the rear lower measuring point; According to the formula: ， ， Obtain soil compression modulus; in, is the volume of soil within the influence range of expansive concrete, is the volume expansion of the expansive concrete in the i-th test pit, is the sum of the volumes of liquid and gas in the initial state of the soil, is the solid volume of the soil in its initial state, is the sum of the volumes of liquid and gas in the compressed state of the soil in the i-th test pit, is the initial porosity ratio of the soil, is the soil porosity ratio of the i-th test pit, is the soil compression modulus, is the compression factor.

2. The test method for obtaining soil compression modulus using expansive concrete according to claim 1, wherein: By arranging pressure sensors at each detection point, the detection pressure value is obtained.

3. The test method for obtaining soil compression modulus using expansive concrete according to claim 1, wherein: The method of obtaining the volume of the expansive concrete after the expansive concrete is completely solidified includes: After the expansive concrete is completely solidified, remove the expansive concrete from the test pit; The volume of expansive concrete was obtained by wax sealing method.

4. The test method for obtaining soil compression modulus using expansive concrete according to claim 1, wherein: Before pouring expansive concrete containing a set amount of expansive agent in the test pit, pour a concrete cushion layer of a set thickness at the bottom of the test pit.

5. The test method for obtaining soil compression modulus using expansive concrete according to claim 4, characterized in that: After the concrete cushion layer is completely solidified, apply lubricating oil on the surface of the concrete cushion layer.

6. The test method for obtaining soil compression modulus using expansive concrete according to claim 1, wherein: After pouring expansive concrete containing a set amount of expansive agent in the test pit, a ballast load is applied to the top of the test pit.

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