KR102218450B1 - Apparatus and Method for Shear Test Using Model Chamber to Analysis of Anchor Behavior on Slopes - Google Patents

Abstract

The present invention relates to a soil shear test apparatus and a soil shear test method using the same. In relation to an anchor installed on the slope for stability and protection of the slope (slope), the soil shear test apparatus and the soil shear test method using the same create an artificial ground on which anchors are installed using earthworks in order to understand the behavior of the anchor according to the situation of various types of slopes, including when activities occur on the slope, induce artificial shear deformation corresponding to the change of the slope in the ground, and can objectively and precisely measure the various structural reactions occurring in the anchor.

Description

Apparatus and Method for Shear Test Using Model Chamber to Analysis of Anchor Behavior on Slopes {Apparatus and Method for Shear Test Using Model Chamber to Analysis of Anchor Behavior on Slopes}

The present invention relates to a soil shear test apparatus for analyzing the behavior of an anchor installed on a slope and a soil shear test method using the same, specifically, in relation to an anchor installed on the slope for stability and protection of the slope (slope/斜面) In order to understand the behavior of anchors according to the situation of various types of slopes, including when there is an activity in the slope, an artificial ground is created with anchors installed using a soil structure and an artificial shear corresponding to the change of the slopes It relates to a "earth shell shear test apparatus and an earth shell shear test method using the same" that can objectively and accurately measure various structural reactions that occur in the anchor after causing deformation to the ground.

As a construction method for reinforcing the slope, an anchor is installed on the slope and a prestress is introduced to the anchor to increase the stability of the slope. "The slope reinforcement method using an anchor" is widely used. Republic of Korea Patent Publication No. 10-2015-0063968 introduces the contents of installing an anchor on a slope using a hydraulic plate in a conventional slope reinforcement method using an anchor.

In the slope reinforcement method using an anchor, there may be a case where the tensile force acting on the anchor installed on the slope ("anchor tension") gradually increases. If the anchor tension increases gradually, the anchor breaks, etc. Occurs, the function of the anchor may be lost, and the stability of the slope may be poor. The increase in anchor tension is caused by a combination of factors. In particular, when activity (sliding) occurs on the slope where the anchor is reinforced, shear and bending stresses act along the active surface, and the shear displacement increases. The more the deformation occurs in the anchor as well. If the activity of the slope continues, an increase in anchor tensile force is caused, and more deformation and displacement of the anchor occurs. The increase in the deformation and displacement of the anchor causes the destruction of the grout body built in the anchor hole of the slope so that the anchor is buried and fixed, and eventually the function of the anchor, that is, the anchor function reinforcing the slope, is lost. Is done.

Therefore, an experimental study on the behavior of the anchor installed on the slope and the behavior of the ground is necessary, and the importance is very high. In particular, an experimental study on the behavior of the anchor and the ground behavior according to the activity of the slope and the resulting shear displacement is very important. However, at present, no test apparatus and test method have been proposed that can objectively, efficiently, accurately and accurately grasp the behavior of anchors and ground in an experimental form in a situation where activity occurs on a slope.

Republic of Korea Patent Publication No. 10-2015-0063968 (published on June 10, 2015).

The present invention was developed in order to overcome the limitations of the prior art as described above, and various types of ground changes including activity (sliding) occur while the anchor is embedded in the slope. The objective is to provide a test apparatus and test method that can be simulated and reproduced using, and objectively, efficiently, accurately and accurately grasp the behavior of the anchor at that time in an experimental form.

In the present invention, in order to achieve the above object, the anchor 2 may be installed in the longitudinal direction, and the earth and sand are filled to include a soil tank 1 having an inner space in which the test ground 200 is built; Tojo (1) is divided into a fixed section (1A) and a transverse section (1B) in the longitudinal direction; The lateral movement section is formed by continuously arranging unit soil modules capable of lateral displacement independently of each other in the longitudinal direction; On one side of the transverse direction of the transverse movement section, a transverse load loading device 5 capable of individually applying a transverse load to each of the unit earthen modules is provided; On the other side of the lateral movement section in the lateral direction, a lateral force measuring device 6 for individually measuring the lateral force expressed in each unit earthen module is provided; In order to realize the constrained pressure state of the anchor 2, it has a configuration including a vertical load device 7 that applies a vertical load by covering the open upper surface of the earth tank 1; With the anchor (2) installed in the soil tank (1) and the test ground (200) formed, the unit soil module is moved horizontally in the horizontal direction by applying a lateral load to the unit soil module individually or in a unitary state. By inducing shear deformation in the test ground 200 built in the soil tank 1, the soil shear test apparatus is provided, characterized in that the anchor installed in the site of the slope and the ground condition are experimentally simulated and reproduced.

In addition, in the present invention, there is provided an earthen shear test method, wherein the earthen shear test method of the present invention uses the earthen shear test apparatus of the present invention; Installing an anchor 2 in the inner space of the earth tank 1 in the longitudinal direction; Building the test ground 200 by filling the soil in the inner space of the soil tank 1 so that the anchor 2 is buried; Implementing a constrained pressure state of the anchor 2 by vertically pressing the test ground 200 using a vertical load device 7; And inducing shear deformation in the test ground 200 built in the soil 1 by horizontally moving the unit soil module in the horizontal direction by simultaneously applying a lateral load to the unit soil module individually or in an integrated state. It has a configuration including, and is characterized in that the test is performed by experimentally simulating and reproducing the condition of the anchor and ground installed on the site of the slope.

According to the earthen shear test apparatus of the present invention and the earthen shear test method using the same, after reproducing the situation in which the anchor is installed on the slope of an actual site using an earthen and an anchor, etc. By applying a lateral load to the module individually or collectively to induce a lateral horizontal displacement, an artificial shear deformation corresponding to the situation of various types of slopes, including when activity occurs on the slope, is generated on the ground, and then anchors and Various structural reactions occurring in the ground are measured objectively and precisely. Therefore, according to the present invention, a very useful effect is exerted that the site situation in which the anchor is constructed can be identically simulated in the laboratory to allow precise experimentation.

1 and 2 are schematic perspective views, respectively, showing the earthen shear test apparatus according to an embodiment of the present invention in different directions.
3 is a schematic plan view of the earthwork shear test apparatus shown in FIG. 1.
FIG. 4 is a schematic longitudinal front view of the earth tank shear test apparatus shown in FIG. 1.
Figure 5 is a schematic perspective view showing only the fixing section of the earthen according to the present invention.
6 is a schematic perspective view showing only the lateral movement section of the earthenware according to the present invention.
7A and 7B are schematic perspective views showing unit earthmoving modules constituting a lateral movement section, respectively.
FIG. 8 is a schematic perspective view showing a different direction of viewing the circle A of FIG. 1.
FIG. 9 is a schematic perspective view showing a different direction of viewing the circle B of FIG. 2.
10 and 11 are schematic perspective views sequentially showing a state in which a cover is covered in a state in which a test ground is formed in a soil tank, respectively.
FIG. 12 is a schematic plan view corresponding to FIG. 3 showing a state in which different lateral loads are applied to each unit earthen module to be individually horizontally displaced.
FIG. 13 is a schematic plan view corresponding to FIG. 12 showing a state in which all of the unit earthmoving modules constituting the lateral movement section are integrated so that they move simultaneously and horizontally displaced over the entire lateral movement section.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. The present invention has been described with reference to the embodiment shown in the drawings, but this is described as an embodiment, by which the technical idea of the present invention and its core configuration and operation are not limited. For convenience, in the entire specification including the claims, the direction in which the anchor is elongated is described as "longitudinal direction", the direction horizontally orthogonal thereto is described as "transverse direction", and the height direction of the tojo is referred to as "vertical direction". Write. And in the present invention, the anchor is understood to include various types of members such as soil nails that are extended in the longitudinal direction and embedded in the ground in addition to meaning "anchors" in the original meaning installed on the ground for the stability of the slope. Should be.

Earthen shear test apparatus 100 of the present invention, an anchor 2 is installed in the earthen 1 in the longitudinal direction and fills the earth to build the test ground 200, but the earthen 1 is in the longitudinal direction It is divided into “fixed section (1A)” and “transverse section (1B)”. In the lateral section, a unit tojo module capable of independently lateral displacement is continuously arranged in the longitudinal direction. Tojo (1) In the state in which the anchor 2 is installed and the test ground 200 is formed, the unit soil module is individually or a plurality of unitary modules are simultaneously moved horizontally in the transverse direction. 200), and the change in anchor axial force (axial force acting on the anchor) caused by the shear deformation of the test ground 200, the form of failure of the test ground 200, and the lateral force acting on each unit soil module And by measuring the lateral displacement, etc., it has a configuration that can objectively, accurately, efficiently and accurately grasp the behavior of the anchor and the behavior of the ground due to the occurrence of activity (activity) on the actual slope where the anchor is installed.

1 and 2 are schematic perspective views showing a schematic shape of an earthen shear test apparatus 100 according to an embodiment of the present invention in different directions. 3 is a schematic plan view of the soil shear test apparatus 100 shown in FIG. 1, and FIG. 4 is a schematic longitudinal front view of the soil shear test apparatus 100 shown in FIG. 1.

Earthen (1) is a member that is formed of a rectangular parallelepiped that is elongated in the longitudinal direction, and the test ground 200 is built by filling the soil in its inner space. )" is divided into two sections. In FIG. 1, the upper part of the soil tank 1 is shown to be open. After construction of the test ground 200, a cover 70 for applying a vertical load is covered in order to simulate a constrained pressure state.

Figure 5 is a schematic perspective view showing only the fixing section (1A) of the soil tank 1, the fixing section (1A) of the soil tank (1) has two vertical lateral walls 10 and a bottom plate 12, In addition, the first end plate 11 is included, and the longitudinal ends facing the upper and lateral movement section are made of an open box-shaped member. A through hole 110 through which the anchor 2 penetrates is formed in the first end plate 11. The fixed section 1A of the soil tank 1 is installed completely fixed to the ground so that it cannot be moved.

The lateral movement section 1B is made up of a plurality of unit earthen modules 3. 6 is a schematic perspective view showing only the lateral movement section 1B of the tojo 1, and Figs. 7 (a) and (b) schematically showing the unit soil modules constituting the lateral movement section 1B, respectively A perspective view is shown. The lateral movement section 1B has a configuration in which an end-side unit tojo module and a plurality of intermediate unit tojo modules are sequentially arranged in succession while going from the front to the rear, that is, toward the fixed section. For convenience, the member number 3b is assigned to the end-side unit tojo module, and the member number 3a is assigned to the intermediate unit tojo module. In addition, in the case of simply describing the "unit earthen module", it should be understood to refer to both the end-side unit earthen module 3b and the intermediate unit earthen module 3a.

As shown in Fig. 7 (a), the intermediate unit earthen module 3a includes two vertical transverse vertical bodies 30 and a floor planar body 31. It consists of a member having a shape facing toward. The end-side unit earthwork module 3b provided at the longitudinal end of the lateral movement section 1B is attached to the two vertical transverse vertical bodies 30 and the floor plane 31 as shown in FIG. 7(b). In addition, a second end plate 32 disposed so as to intercept between the two transverse vertical bodies 30 at the longitudinal ends is further provided. A through hole 110 through which the anchor 2 passes is formed at a position of the second end plate 32 facing the through hole 110 of the first end plate 11.

In the present invention, each of the unit earthen modules can be individually horizontally moved. When the unit earthen module moves horizontally, it is necessary to minimize factors that interfere with horizontal movement such as friction. In addition, when the unit earthen module moves horizontally, it is necessary to make a state where only linear motion in the transverse direction is possible and motion in other directions is not possible.

To this end, in the case of the embodiment shown in the drawings, guide rails 40 extending in the transverse direction are installed under each of the unit soil modules, and a rolling wheel 4 is provided on the bottom surface of the floor plane 31 of each unit soil module. By installing, the unit earthen module is placed on the guide rail 40, and the rolling wheel 4 is guided along the guide rail 40 to move the cloud. According to this configuration, friction generated during horizontal movement of the unit earthen module can be minimized, and since it is guided by the guide rail 40 to move horizontally, there is an advantage in that it can move while maintaining the correct transverse direction. Of course, when the unit earthen module moves horizontally, a method of minimizing factors that interfere with horizontal movement, such as friction, is not limited thereto, and for example, the lower surface of the floor planar body 31 of each unit earthen module is made of a low friction material For example, it is possible to apply various measures such as coating with Teflon, etc.) or attaching and installing a member made of a low-friction material to slide in the horizontal direction.

In the present invention, the unit earthen module can be independently and individually horizontally moved in the horizontal direction, and in the test using the earthen shear test apparatus 100 of the present invention, each of the individual unit earthen modules or a plurality of unit earthen modules as necessary At the same time, the force in the transverse direction, that is, the transverse load is loaded. To this end, a transverse load loading device 5 is provided on one side in the transverse direction of the unit earthen module. FIG. 8 is a schematic perspective view showing in different directions toward the circle A of FIG. 1 to show the configuration of the lateral load loading device 5 provided in the embodiment of the present invention in detail. Specifically, in the embodiment illustrated in the drawing, the lateral load loading device 5 includes a lateral vertical body 30 present on one side of the unit earthen module and a reaction force member 50 positioned at an interval in the lateral direction, and a lateral vertical body It is configured to include a pressing member 51 that applies a force to the unit earthen module by being arranged at the interval between the 30 and the reaction force member 50 to expand and contract. The force member 51 may be configured with a jack device or the like.

The pressing member 51 is provided individually for each unit tojo module. The reaction force member 50 may also be provided individually for each unit earthen module, but may be formed of a member that is extended in the longitudinal direction so that the entire unit earthen module can be shared and is fixedly installed on the ground. When the pressing member 51 is elongated, a lateral force acts on the unit earthen module, and accordingly, a horizontal displacement in the lateral direction can occur.

In the above configuration, each pressing member 51 may be individually controlled to individually apply a lateral load to each unit earthen module, but if necessary, it may be necessary to simultaneously apply the same lateral load to a plurality of unit earthen modules. In this case, although not shown in the drawing, the same lateral load is generated by operating the force member 51 in a state in which a bonding material consisting of a plate member or a beam member extending in the longitudinal direction is integrally installed and integrated into the required number of unit earthen modules. It can also be made to be applied to each of the Tojo modules.

In the present invention, a lateral force measuring device 6 for measuring the force expressed in the unit earthen module is installed on the lateral side opposite to the lateral side, that is, the lateral side where the lateral load and loading device 5 is installed. FIG. 9 is a schematic perspective view showing the configuration of the lateral force measuring device 6 provided in the embodiment of the present invention in different directions toward the circle B of FIG. 2. Specifically, in the embodiment illustrated in the drawings, the lateral force measuring device 6 includes a load cell 61 and a reaction force 60 installed in contact with the lateral vertical body 30 of the unit earthen module. Is composed. The load cell 61 is individually installed for each of the plurality of unit earthen modules. When the unit earthen module is horizontally displaced in the horizontal direction, the load cell 61 measures the lateral force accordingly.

Like the reaction force member 50 described above, the reaction arm 60 may be separately provided for each unit earthen module, or it is a member fixedly installed on the ground by extending longitudinally so that the entire unit earthen module can be shared. It can be done. If necessary, a displacement meter 62 capable of measuring the lateral horizontal displacement of the unit soil module may be further installed on the side of the unit soil module in the lateral direction on which the lateral force measuring device 6 is installed.

The test ground 200 is constructed by filling the soil in the inner space of the soil tank 1, and prior to the construction of the test ground 200, the anchor 2 is disposed in the internal space of the soil tank 1 in the longitudinal direction, Both ends of the anchor 2 in the longitudinal direction are fixed to both longitudinal outer surfaces of the earth tank 1, respectively. In the drawing, reference numeral 21 denotes a fixing member 21 that is closely installed to the longitudinal outer surface of the earth tank 1 in order to fix the end of the anchor 2, respectively, and the fixing member 21 re-tension the anchor 2 It is desirable to have a configuration that can be fixed. Longitudinal load cells may be installed on both longitudinal outer surfaces of the earth tank 1 to measure the magnitude and change of the cross-sectional force generated in the anchor 2, that is, the anchor tensile force.

Anchors installed on the ground of the site are subjected to pressure not only in the vertical direction but also in the horizontal direction. That is, the restraining pressure acts on the anchor in many ways. In this way, the soil shear test apparatus 100 of the present invention has a vertical load for applying a vertical load to the test ground 200 built in the soil tank 1 so that the constraining pressure is applied to the anchor, that is, the constrained pressure state can be identically simulated. A load device 7 is provided. The vertical load device 7 includes a cover 70 installed to cover the entire open upper surface of the earthen tank 1, and a downward pressing device for pressing the cover 70 downward. 10 and 11 are schematic perspective views sequentially showing a state in which a cover 70 is covered in a state in which the test ground 200 is formed in the soil 1, respectively. In the drawing, reference numeral 71 denotes a downward pressing member 71 that directly presses the cover 70.

In the following, a test method using the soil shear test apparatus 100 according to the present invention will be described.

According to the above description, an earth tank 1 consisting of a fixed section 1A and a lateral moving section 1B is assembled and installed, and an anchor 2 is disposed in the longitudinal direction therein. At this time, according to the test purpose and test conditions, the anchor 2 can be tensioned.

Subsequently, the test ground 200 is constructed by filling the soil inside the soil tank 1 so that the anchor 2 is buried. After the test ground 200 is constructed, the cover 70 is covered over the test ground 200. At this time, in accordance with the test purpose and conditions, the cover 70 is pressed with the downward force member 71 to make the anchor 2 embedded in the test ground 200 into a constraining pressure state corresponding to the site.

In the state where the test ground 200 is formed, the lateral load loading device 5 is operated to apply a lateral load suitable for the test purpose and condition at the same time to the unit earthwork module individually or in a united state. Using the lateral force measuring device 6, the lateral force expressed in the unit earthen module is measured. At this time, if the displacement meter 62 is provided, the horizontal displacement of each unit earthen module is measured using it.

FIG. 12 is a schematic plan view corresponding to FIG. 3 showing a state in which different lateral loads are applied to each unit earthen module to be individually horizontally displaced, and FIG. 13 is a schematic plan view of all the unit earthen units forming the transverse movement section 1B. A schematic plan view corresponding to FIG. 12 is shown showing a state in which the module is displaced horizontally for the entire lateral movement section 1B in an integrated state to move simultaneously. For convenience, the illustration of the cover 70 is omitted in FIGS. 12 and 13. As described above, in the earthen shear test apparatus 100 of the present invention, each unit earthen module may individually move horizontally in the horizontal direction. Therefore, according to the purpose and conditions of the test, a lateral load is individually applied to the unit earthen module as illustrated in FIG. 12, or as illustrated in FIG. 13, a lateral load is applied simultaneously while a plurality of unit earthen modules are integrated. By making the horizontal movement to be induced, the test ground 200 built in the earthen 1 is induced in various forms in accordance with the purpose of the test. The tester measures the change of the anchor axial force (axial force acting on the anchor) caused by the shear deformation of the test ground 200, the failure type of the test ground 200, and the lateral force and lateral displacement acting on each of the unit soil modules. It is possible to objectively, accurately, efficiently and precisely grasp the behavior of the anchor and the behavior of the ground due to the occurrence of activity on the actual slope where the is installed.

As described above, according to the earthen shear test apparatus 100 of the present invention and the earthen shear test method using the same, in a form that simulates the situation in which the anchor is installed on the actual slope, an anchor is installed on the earthen and an artificial test ground is created. After creating a constrained pressure state, a lateral load is applied individually or collectively to the unit soil modules that make up the soil, causing a horizontal displacement in the lateral direction, which is suitable for various types of slope conditions, including when activity occurs on the slope. After artificial shear deformation is reproduced on the ground, various structural reactions occurring in the anchor and ground are measured objectively and precisely. That is, according to the present invention, it is possible to accurately experiment by simulating the site situation in which the anchor is installed in the laboratory.

1: Tojo
1A: Fixed section
1B: lateral movement section
2: anchor
3a: middle unit earthen module
3b: End-side unit soil module
4: cloud wheel
5: Lateral load loading device
6: Lateral force measuring device
7: Vertical load device
100: soil shear test device
200: test ground

Claims (10)

It includes an earth tank having an inner space in which an anchor can be installed in the longitudinal direction and the soil is filled and the test ground is built;
Tojo is divided into a fixed section and a lateral moving section in the longitudinal direction;
The lateral movement section is formed by successively arranging a plurality of unit soil modules capable of transverse displacement independently, respectively;
On one side of the transverse direction of the transverse movement section, a transverse load loading device capable of individually applying a transverse load to each unit earthmoving module is provided;
On the other side of the lateral movement section in the lateral direction, a lateral force measuring device for individually measuring the lateral force generated by each unit earthen module is provided;
In order to realize the constraining pressure state of the anchor, a vertical load device that applies a vertical load by covering the open upper surface of the earthen is provided.
Anchor is installed in the soil tank and the test ground is formed, and a lateral load is applied to the unit soil module individually or in an integrated state, and the unit soil module is horizontally moved in the horizontal direction to shear the test ground built in the soil tank. By causing the deformation, the soil shear test apparatus, characterized in that the anchor and ground conditions installed on the site of the slope are experimentally simulated and reproduced. The method of claim 1,
The fixed section of the earthen shell includes two vertical transverse side walls, a bottom plate, and a first end plate, and the longitudinal end facing the upper and transverse section is made of an open box-shaped member;
The unit soil module forming the lateral movement section consists of an intermediate unit soil module and an end unit soil module. The intermediate unit soil module includes two vertical horizontal vertical bodies and a floor planar body. Consisting of a member having a shape in which the open portion faces upward, and the end-side unit earthen module is composed of a member including two vertical transverse vertical bodies, a floor planar body, and a second end plate;
Earthwork shear test apparatus, characterized in that the first end plate and the second end plate are formed with through-holes through which the anchor passes. The method according to claim 1 or 2,
The transverse load loading device applies a force to the unit earthen module by expanding and contracting a reaction member positioned at an interval in the transverse direction from the lateral vertical body existing on one side of the unit earthen module, and the space between the horizontal vertical body and the reaction member. Earthen shear test apparatus, characterized in that configured to include a pressing member. The method according to claim 1 or 2,
The lateral force measuring device is configured to include a load cell that is individually installed for each of a plurality of unit soil modules, and a reaction arm supporting the load cell. The method according to claim 1 or 2,
The vertical load device is configured to include a cover installed so as to cover the entire open upper surface of the soil tank, and a downward force device for pressing the cover downward. It is divided into a fixed section and a lateral moving section in the vertical direction, and the lateral moving section is provided with a soil tank formed by continuously arranging a plurality of unit soil modules that can independently laterally displace in the vertical direction, and the lateral direction of the lateral movement section. On one side, a lateral load loading device that can individually apply a lateral load to each unit soil module is provided, and on the other side of the lateral movement section in the lateral direction, a lateral force measuring device that individually measures the lateral force generated by each unit soil module is provided. It uses an earthen shear test apparatus having a configuration equipped with a vertical load device that applies a vertical load by covering the open upper surface of the wall;
Installing an anchor extending in the longitudinal direction in the inner space of the earth tank;
Building a test ground by filling the soil in the inner space of the soil so that the anchor is buried;
Implementing a constrained pressure state of the anchor by vertically pressing the test ground using a vertical load device; And
Inducing shear deformation in the test ground built in the soil by horizontally moving the unit soil module in the horizontal direction by simultaneously applying a lateral load to the unit soil module individually or in a unitary state. A soil shear test method, characterized in that the test is performed by experimentally simulating and reproducing the condition of the anchor installed on the site of the slope and the ground. The method of claim 6,
In the earthen shear test apparatus, the anchorage section of the earthen shell includes two vertical transverse side walls, a bottom plate, and a first end plate, and the longitudinal end facing the upper and transverse section is made of an open box-shaped member. ;
The unit soil module forming the lateral movement section consists of an intermediate unit soil module and an end unit soil module. The intermediate unit soil module includes two vertical horizontal vertical bodies and a floor planar body. Consisting of a member having a shape in which the open portion faces upward, and the end-side unit earthen module is composed of a member including two vertical transverse vertical bodies, a floor planar body, and a second end plate;
The first end plate and the second end plate is characterized in that the through-hole through which the anchor penetrates is formed. The method according to claim 6 or 7,
In the earthwork shear test apparatus, the lateral load loading device is a reaction force member positioned at an interval in the transverse direction with a lateral vertical body existing on one side of the unit earth tank module, and a unit earth tank by being arranged at a distance between the horizontal vertical body and the reaction force member. Earthen shear test method, characterized in that comprising a force member for applying a force to the module. The method according to claim 6 or 7,
The lateral force measuring device in the earthwork shear test apparatus comprises a load cell individually installed for each of a plurality of unit earthen modules, and a reaction arm supporting the load cell. The method according to claim 6 or 7,
In the earthen shear test apparatus, the vertical load device comprises a cover installed to cover the entire open upper surface of the earthen tank, and a downward force device for pressing the cover downward.

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