Visual test device for additional stress of foundation soil body

Abstract

The utility model discloses a visual test device for additional stress of a foundation soil body. The visual test device comprises a model box, the foundation soil body arranged in the model box, an independent foundation, a force application device for applying a vertical load to the independent foundation, and a detection device for detecting the additional stress in the foundation soil body, the detection device comprises a bag and a pressure measuring module connected with the bag; wherein the number of the bags is multiple groups, and the multiple groups of bags are arranged below the independent foundation and are arranged in the length or / and height direction of the model box; the number of the pressure measuring modules is multiple, and each pressure measuring module is connected with one bag. The foundation soil body additional stress visual test device can simply and quickly measure the size and the distribution range of the foundation soil body additional stress.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of test ground soil body additional stress, specifically related to a ground soil body additional stress visualization test device. BACKGROUND

[0002] Additional stress refers to the stress increment in the ground soil body when the upper foundation is subjected to external load, which is the main reason for the deformation of the foundation, and only within the diffusion angle theta range, additional stress exists. Therefore, it is necessary to study additional stress and its specific parameters, which is conducive to ensuring the safety and stability of the foundation in actual engineering. The research on the additional stress of the ground soil body mainly has the following two aspects: one is the distribution range of the additional stress of the ground soil body, and the other is the determination of the diffusion angle theta. If the water head height / additional stress (distribution range, diffusion angle theta) can be observed in real time and dynamically by naked eye observation and with the aid of computer equipment, it will bring great convenience for the research and teaching of the additional stress of the ground soil body. However, at present, there is no dynamic visualization test device and method for quantitatively testing the distribution range of additional stress and the diffusion angle of additional stress. CONTENT OF THE UTILITY MODEL

[0003] The utility model discloses in order to overcome the insufficient of prior art, provide a ground soil body additional stress visualization test device, the ground soil body additional stress visualization test device can simply, fastly measure the size and distribution range of ground soil body additional stress.

[0004] The technical scheme for solving the above technical problem of the utility model is:

[0005] A ground soil body additional stress visualization test device, including model box, ground soil body, independent foundation, force device for applying vertical load to the independent foundation and detection device for detecting additional stress in the ground soil body are arranged in the model box, the detection device includes a bag and a pressure measuring module connected with the bag, wherein the bag is multiple groups, multiple groups of bags are arranged below the independent foundation, and are arranged along the length or / and height direction of the model box, the pressure measuring module is multiple groups, and each group of pressure measuring modules is connected with a group of bags.

[0006] Preferably, the plurality of groups of the bladder bags respectively constitute a first bladder bag layer, a second bladder bag layer and a third bladder bag layer, wherein the first bladder bag layer is located above the second bladder bag layer and below the independent foundation; the plurality of groups of the bladder bags in the first bladder bag layer are equidistantly arranged along the length direction of the model box; the second bladder bag layer is located at the junction of the bearing layer and the soft lower layer in the foundation soil body, and the plurality of groups of the bladder bags in the second bladder bag layer are equidistantly arranged along the length direction of the model box; the third bladder bag layer is located below the central point of the bottom of the independent foundation and equidistantly arranged along the height direction of the model box.

[0007] Preferably, the interval between the adjacent two groups of the bladder bags in the first bladder bag layer, the second bladder bag layer and the third bladder bag layer is 20 cm.

[0008] Preferably, the pressure measuring module is a pressure pipe, a water column is arranged in the pressure pipe, and a scale table is arranged outside the pressure pipe; when the force applying device applies the vertical load on the independent foundation, the gas in the bladder bag promotes the water column in the pressure pipe to rise.

[0009] Preferably, a pore pressure sensor is arranged at the connecting position of the pressure pipe and the bladder bag; and the pore pressure sensor is connected with a computer device.

[0010] Preferably, the force applying device comprises a support frame arranged on the model box and a jack arranged on the support frame, wherein the jack is installed on the support frame, and the output shaft of the jack is located directly above the central point of the top of the independent foundation.

[0011] Preferably, the support frame comprises profile steel columns arranged around the model box; the two profile steel columns located on the left are connected through a first steel plate; the two profile steel columns located on the right are connected through a second steel plate; the first steel plate and the second steel plate are connected through two groups of counterforce cross beams; the two groups of counterforce cross beams are arranged side by side; and the jack is installed on the two groups of counterforce cross beams, and the output shaft of the jack is located directly above the central point of the top of the independent foundation.

[0012] Preferably, the support frame is welded to the outside of the model box, and the height of the profile steel column is 4 m.

[0013] Preferably, a pressure sensor is installed on the jack, and the pressure sensor is used for detecting the size of the vertical load applied by the jack.

[0014] Preferably, the length, width and height of the bottom of the model box are 4 m, 3 m and 2 m respectively; and the length and width of the bottom of the independent foundation are 2 m and 1.5 m respectively.

[0015] Compared with the prior art, the utility model has the advantages and beneficial effects that:

[0016] 1、The foundation soil additional stress visualization test device can realize rapid detection on the size and distribution range of the additional pressure of the foundation soil, and the size and distribution range of the additional pressure of the foundation soil can be quickly obtained without using complex detection instruments / equipment during the detection process, which is especially suitable for some places lacking advanced detection instruments / equipment.

[0017] 2、The foundation soil additional stress visualization test device has low requirements on the properties and hardness of the foundation soil, can be applied to various types of foundation soil, and has the advantages of simple operation and low implementation cost.

[0018] 3、The detection mechanism of the foundation soil additional stress visualization test device is simple, convenient to operate and does not completely rely on professional personnel, has low requirements on the properties and hardness of the foundation soil, can be applied to various types of foundation soil, and the detection personnel can conveniently and directly obtain simple and understandable visualization results through naked eye observation, thereby saving test cost and human resources. BRIEF DESCRIPTION OF DRAWINGS

[0019] Fig. 1 It is a structural schematic view of the foundation soil additional stress visualization test device.

[0020] Fig. 2 It is a schematic view of the arrangement of the bag.

[0021] Fig. 3 It is a principle view of calculating the diffusion angle of the additional stress of the foundation soil.

[0022] In the figure: 1 - model box; 11 - support frame; 2 - jack; 3 - independent foundation; 4 - bag; 5 - pressure measuring pipe. DETAILED DESCRIPTION

[0023] The utility model will be described in further detail below in combination with embodiments and drawings, but the implementation mode of the utility model is not limited thereto.

[0024] Embodiment 1

[0025] Referring to Figs. 1-3 , the foundation soil additional stress visualization test device comprises a model box, a foundation soil arranged in the model box, an independent foundation, a force applying device for applying vertical load to the independent foundation, and a detection device for detecting additional stress in the foundation soil.

[0026] In this embodiment, the length x width x height of the bottom of the model box is 4m x 3m x 2m; the length x width of the bottom of the independent foundation is 2m x 1.5m.

[0027] Referring to Figs. 1-3 , the detection device comprises a bag and a pressure measuring module connected with the bag; wherein the bag is in multiple groups, and the multiple groups of bags are arranged below the independent foundation and along the length or / and height direction of the model box; the pressure measuring module is in multiple groups, and each group of pressure measuring modules is connected with a group of bags; the pressure measuring module is a pressure measuring pipe, and the model box is provided with a avoiding hole for avoiding the pressure measuring pipe; the avoiding hole is arranged on one side of the model box; the inlet of the pressure measuring pipe is communicated with the bag; in this embodiment, a water column is arranged in the pressure measuring pipe, and a scale table is arranged outside the pressure measuring pipe; when the force applying device applies vertical load on the independent foundation, the gas in the bag promotes the water column in the pressure measuring pipe to rise; by observing the water head height of the pressure measuring pipe, the change value of the water head height can be obtained; by calculating the product of the specific gravity of the water column in the pressure measuring pipe and the change value of the observed water head height, the pore water pressure in the pressure measuring pipe can be calculated as the additional pressure of the foundation soil body at this position; by observing the change value of the water head height in each pressure measuring pipe, the distribution range of the additional pressure of the foundation soil body can be determined.

[0028] Referring to Figs. 1-3 , the multiple groups of bags respectively constitute a first bag layer, a second bag layer and a third bag layer, wherein,

[0029] The first bag layer is located above the second bag layer and below the independent foundation; the multiple groups of bags in the first bag layer are equidistantly arranged along the length direction of the model box; the bag and the pressure measuring pipe are installed on the bottom surface of the independent foundation, and after the independent foundation is subjected to vertical load, the size and distribution range of the pressure of the independent foundation can be quantitatively tested, so as to calculate the average pressure of the bottom surface of the independent foundation.

[0030] The second bag layer is located at the junction of the bearing layer and the weak underlayer of the foundation soil body, and the multiple groups of bags in the second bag layer are equidistantly arranged along the length direction of the model box;

[0031] The third bag layer is located below the center point of the bottom of the independent foundation and is equidistantly arranged along the height direction of the model box; by arranging the third bag layer, the vertical distribution range of the additional pressure of the foundation soil body can be used, that is, whether there is additional pressure distribution in different depths of the foundation soil body can be detected;

[0032] In this embodiment, the spacing between the adjacent two groups of bags in the first bag layer, the second bag layer and the third bag layer is 20 cm.

[0033] Referring to Figs. 1-3The force applying device comprises a support frame arranged on the model box and a jack arranged on the support frame, wherein the support frame comprises profile steel columns arranged around the model box; two profile steel columns on the left are connected through a first steel plate; two profile steel columns on the right are connected through a second steel plate; the first steel plate and the second steel plate are connected through two groups of counterforce cross beams; the two groups of counterforce cross beams are arranged side by side; the jack is installed on the two groups of counterforce cross beams, and an output shaft of the jack is located directly above a top center point of the independent foundation; a vertical load of 0-10KN can be applied to the top center point of the independent foundation through the jack; a pressure controller can be installed on the jack, and the pressure controller can control the size of the load applied by the jack.

[0034] In the embodiment, the support frame is welded on the outside of the model box, and the model box adopts a light steel structure material; the height of the profile steel column is 4m.

[0035] Referring to Figs. 1-3 , the use method of the foundation soil body additional stress visualization test device comprises the following steps:

[0036] The model box is filled with the foundation soil body required for the test; during the process of filling the foundation soil body, the bag is arranged at the corresponding position of the foundation soil body, and each bag is connected with each pressure measuring module;

[0037] The independent foundation is placed above the foundation soil body, and the center point at the bottom of the independent foundation is aligned with the vertically arranged bag;

[0038] The force applying device applies a vertical load to the center point at the top of the independent foundation, and the additional stress of the foundation soil body at each position is detected through the pressure measuring device, so that the distribution range of the additional stress of the foundation soil body is obtained; specifically,

[0039] The change value h of the water head height is obtained by observing the change of the height of the water column in the pressure measuring pipe; the change value h of the water head height is obtained by observing the change of the height of the water column in the pressure measuring pipe; and the change value h of the water head height is obtained by observing the change of the height of the water column in the pressure measuring pipe. w The change value h of the water head height is obtained by observing the change of the height of the water column in the pressure measuring pipe; the change value h of the water head height is obtained by observing the change of the height of the water column in the pressure measuring pipe; and the change value h of the water head height is obtained by observing the change of the height of the water column in the pressure measuring pipe.

[0040] u=γ w h;

[0041] The size of the additional stress of the foundation soil body can be quickly calculated through the above formula, and the distribution range of the additional stress of the foundation soil body is quickly obtained according to the change value h of the water head height in each pressure measuring pipe, wherein the higher the change value h of the water head height, the greater the additional stress corresponding to the position.

[0042] Since additional stress only exists within the range of the diffusion angle θ, after obtaining the distribution range of the additional stress and determining the bottom dimensions (known dimensions) of the independent foundation, the diffusion angle of the additional stress in the foundation soil can be calculated based on the distribution range of the additional stress in the foundation soil and the bottom dimensions of the independent foundation.

[0043]

[0044] In the formula: B is the distribution range of additional stress, expressed in units of length; b is the bottom length of the independent foundation; and H is the distance from the bottom surface of the independent foundation to the top surface of the weak underlying layer in the foundation soil.

[0045] Traditionally, the determination of the additional stress and diffusion angle θ at the top surface of the weak underlying layer in the foundation soil requires following the specifications in foundation engineering manuals. The formula for determining the additional stress is as follows:

[0046]

[0047] In the formula: l and b are the length and width of the base of the independent foundation, respectively, and p k The average pressure at the bottom of the independent foundation (which can be measured through the first pocket layer), σ c denoted as , z is the self-weight stress value of the soil at the bottom of the independent foundation, z is the distance from the bottom of the independent foundation to the top surface of the weak underlying layer in the foundation soil, and θ is the diffusion angle, which is determined as shown in Table 1.

[0048] Table 1: Ground pressure diffusion angle θ

[0049]

[0050] In the table: E s1 E represents the compression modulus of the upper soil layer. s2 Let z be the compression modulus of the underlying soil, z be the distance from the bottom surface of the foundation to the top surface of the weak underlying layer, and b be the width of the bottom edge of the foundation.

[0051] A comparison of the two reveals that the calculation method for the diffusion angle θ in the visualization test device for additional stress in foundation soil of this invention is simpler, requires less professional expertise from the testing personnel, and is more suitable for widespread use.

[0052] The foundation soil body additional stress visualized test device has the advantages of simple structure, convenient installation and operation, low implementation cost, no need of precise instruments and equipment during detection of additional pressure of each position of the foundation soil body, simple post-maintenance, low maintenance cost, high applicability to some backward or equipment-lacking areas or places, low detection cost and post-maintenance cost, no need of complex detection instruments / equipment, low professional ability requirement for detection personnel, and the ordinary personnel can detect the size, distribution range and diffusion angle of the additional stress of the foundation soil body after simple training, and the use method / detection method of the foundation soil body additional stress visualized test device is easy to use, and thus, the foundation soil body additional stress visualized test device is convenient to use.

[0053] In the embodiment, the depth of the junction of the bearing layer and the soft underlayer of the foundation soil body needs to be determined by the survey report of the foundation soil body.

[0054] Embodiment 2

[0055] The embodiment is different from the embodiment 1 in that:

[0056] The hole pressure sensor is arranged at the position where the pressure pipe is connected with the bag; the hole pressure sensor is connected with the computer device; correspondingly, the pressure sensor is arranged on the jack, and the pressure sensor is connected with the computer device, so that the vertical load applied by the jack is controlled by the computer device.

[0057] The embodiment collects the data of the hole pressure sensor at each pressure pipe by the computer device, and then the size, distribution range and diffusion angle of the additional stress of the foundation soil body are calculated more quickly by the calculation method in the embodiment 1.

[0058] The above is the preferred embodiment of the utility model, but the embodiment of the utility model is not limited by the above content, any change, modification, replacement, combination and simplification without departing from the spirit and principle of the utility model should be equivalent replacement, which is included in the protection scope of the utility model.

Claims

1. An apparatus for visualizing additional stress in a ground mass, characterized in that, The utility model relates to a model box, the ground body of setting in the model box, independent foundation, the force device for the vertical load of being used to the independent foundation is applied and the detection device for the additional stress of being used to the detection in the ground body, the detection device includes the bag and the pressure measuring module connected with the bag, wherein the bag is multiple groups, multiple groups bag sets below the independent foundation and along the length or / and height direction of the model box is arranged, the pressure measuring module is multiple groups, and each group pressure measuring module is connected with a group bag.

2. The ground soil mass additional stress visualization test apparatus according to claim 1, characterized by, Multiple groups bag respectively constitutes the first bag layer, the second bag layer and the third bag layer, wherein the first bag layer is located above the second bag layer and below the independent foundation, multiple groups bag in the first bag layer is equidistantly arranged along the length direction of the model box, the second bag layer is located at the junction of the bearing stratum and the weak underlayer in the ground body, and multiple groups bag in the second bag layer is equidistantly arranged along the length direction of the model box, the third bag layer is located below the center point of the bottom of the independent foundation and is equidistantly arranged along the height direction of the model box.

3. The ground soil mass additional stress visualization test apparatus according to claim 2, characterized by, The interval between adjacent two groups of bags in the first bag layer, the second bag layer and the third bag layer is 20cm.

4. The ground soil mass additional stress visualization test apparatus according to claim 1, characterized by, The pressure measuring module is a pressure measuring tube, a water column is arranged in the pressure measuring tube, and a scale table is arranged outside the pressure measuring tube, when the force device applies vertical load on the independent foundation, the gas in the bag promotes the water column in the pressure measuring tube to rise.

5. The ground soil additional stress visualization test apparatus according to claim 4, characterized by, A pore pressure sensor is arranged at the connecting part of the pressure measuring tube and the bag, and the pore pressure sensor is connected with a computer device.

6. The ground soil additional stress visualization test apparatus according to claim 5, wherein The force device includes a support frame arranged on the model box and a jack arranged on the support frame, wherein the jack is installed on the support frame, and the output shaft of the jack is located directly above the center point of the top of the independent foundation.

7. The ground soil mass additional stress visualization test apparatus according to claim 6, characterized by, The support frame includes profile steel columns arranged around the model box, two profile steel columns on the left are connected by a first steel plate, two profile steel columns on the right are connected by a second steel plate, the first steel plate and the second steel plate are connected by two groups of counterforce cross beams, the two groups of counterforce cross beams are arranged side by side, and the jack is installed on the two groups of counterforce cross beams, and the output shaft of the jack is located directly above the center point of the top of the independent foundation.

8. The ground soil mass additional stress visualization test apparatus according to claim 7, characterized by, The support frame is welded outside the model box, and the height of the profile steel column is 4m.

9. The ground soil mass additional stress visualization test apparatus according to claim 6, characterized by, A pressure sensor is installed on the jack, and the pressure sensor is used to detect the size of the vertical load applied by the jack.

10. The ground soil mass additional stress visualization test apparatus according to claim 1, characterized by, The length, width and height of the bottom of the model box are 4m, 3m and 2m respectively, and the length and width of the bottom of the independent foundation are 2m and 1.5m respectively.

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