A vertical direct shear creep instrument

Abstract

The present invention provides a vertical direct shear creep instrument, which includes an instrument table, a shear box, a dial indicator and a pressurizing system. A vertical baffle is provided on the instrument table. The shear box is composed of a first box body and a second box body to form an inner cavity for holding soil samples. The pressurizing system includes a horizontal axial pressure weight system and a vertical shear force weight system. The horizontal axial pressure weight system includes a fixed pulley, a steel hinge wire, and a first weight group; the vertical shear force weight system includes a second weight group suspended at the bottom of a second box body suspension rod; the second box body slides down relative to the first box body under the action of gravity and the second weight group. The present invention can avoid the force loss of the traditional direct shear instrument when converting vertical gravity into horizontal shear force. The instrument structure is simpler, the force is clearer, and the instrument cost is lower.

Description

Technical Field

[0001] The invention relates to the technical field of geotechnical indoor test devices. Background Art

[0002] The direct shear creep test refers to a test that shears a soil sample on a specific surface, keeps the shear stress constant, and measures the shear displacement over time. The current direct shear creep tester uses a basic force mode of applying axial pressure vertically and shearing horizontally. The vertical gravity is converted into horizontal force by hooking a weight on a pulley to provide shear force for the sample. Since the shear force is usually much larger than the axial pressure, there will be a certain loss after the pulley converts the direction of the force, and the actual shear force needs to be tested through a steel ring. Summary of the invention

[0003] In order to make up for the deficiencies of the prior art, the present invention provides a vertical direct shear creep instrument which changes the axial pressure, shear force application mode and direction of the instrument.

[0004] In order to achieve the above-mentioned invention object, the present invention adopts the following technical solutions:

[0005] A vertical direct shear creep instrument, comprising an instrument platform, a shear box, a dial indicator and a pressurizing system.

[0006] The instrument table is provided with a vertical baffle, and the table near the vertical baffle has a through hole that runs through the table from top to bottom.

[0007] The shear box is composed of a first box body and a second box body to form an inner cavity for containing soil samples. The first box body is an annular shell with two open ends. The first box body is placed on the instrument table so that one open end is connected to the opening of the second box body, and the other open end is closed by a pressure cover pulled by a steel hinge wire. The open end of the second box body is connected to the first box body, and the closed end opposite to the open end is provided with a pulley block in sliding contact with a vertical baffle.

[0008] The dial of the dial indicator is relatively fixedly connected to the instrument table, and the spring contact head of the dial indicator contacts the top of the second box body.

[0009] The pressurization system includes a horizontal axial pressure weight system and a vertical shear force weight system. The horizontal axial pressure weight system includes a fixed pulley mounted on the instrument table, a steel hinge wire that is fixedly connected to the pressure cover and then passes around the fixed pulley and hangs down, and a first weight group that is directly or indirectly connected to the hanging end of the steel hinge wire; the vertical shear force weight system includes a hanging rod fixed to the lower bottom surface of the second box body and passing through the perforated hole on the instrument table surface, and a second weight group hung at the bottom of the hanging rod; the second box body slides down relative to the first box body under the action of gravity and the second weight group.

[0010] Specifically, the instrument table top is supported by four legs, kept horizontal, and perpendicular to the upright baffle.

[0011] As a preferred solution, the vertical baffle is provided with a track groove for the pulley block to slide vertically.

[0012] Specifically, the dial of the dial indicator is fixed on the upright baffle.

[0013] As a preferred solution, the contact surfaces of the first box body and the second box body are respectively provided with vertical sliding grooves and sliding blocks for the second box body to slide vertically relative to the first box body and to fit each other.

[0014] As a preferred embodiment, the horizontal axial pressure weight system also includes a lever, the fulcrum of the lever is hinged to the side of the instrument table, the end of the steel hinge is fixedly connected to the lever body, and the first weight group is suspended at one end of the lever away from the fulcrum.

[0015] Furthermore, the lever is a U-shaped lever consisting of two longitudinal rods and a cross rod connected between the ends of the two longitudinal rods, the head end of the longitudinal rod is hinged to the side of the instrument table, and the first weight group is suspended in the middle of the cross rod.

[0016] The pressure cover extends to both sides to form an extension end, each extension end is connected to the head end of the steel strand on the same side, and the end of the steel strand is connected to the two longitudinal rods of the lever. The distance between the two extension ends of the pressure cover is greater than the width of the shear box to avoid obstruction of the shear box.

[0017] As a preferred solution, a detachable axial connecting bolt is provided between the first box body and the second box body. When the axial connecting bolt is removed, the second box body can slide down relative to the first box body under the action of force.

[0018] The invention achieves the purpose of simplifying the instrument, avoiding shear force loss and eliminating the steel ring by changing the axial force and shear force application mode and application direction of the instrument. The invention has simple operation and strong feasibility and is an ideal direct shear creep test instrument. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The technical solution of the present invention is now further described in conjunction with the accompanying drawings.

[0020] Figure 1 It is the side view of the vertical direct shear creep instrument;

[0021] Figure 2 This is the front view of the vertical direct shear creep instrument;

[0022] Figure 3 This is the back view of the vertical direct shear creep instrument;

[0023] Figure 4 It is the top view of the vertical direct shear creep instrument;

[0024] Figure 5 This is a schematic diagram of the shear box structure before shearing;

[0025] Figure 6 Schematic diagram of the shear box displacement after shearing.

[0026] Wherein: baffle 101, dial indicator 102, second box body 103, suspension rod 103.1, first box body 104, pulley block 105, pressure cover 106, steel strand 107, instrument table 108, first weight group 109, second weight group 110, soil sample 111, fixed pulley 112, lever 113, longitudinal rod 113.1, cross rod 113.2, connecting bolt 114 DETAILED DESCRIPTION

[0027] The following are merely examples of implementation of the present invention and are not intended to limit the scope of the present invention. That is, any insubstantial changes and modifications made within the scope of the present invention should still fall within the scope of the present invention.

[0028] like Figures 1 to 4 Each figure shows a vertical direct shear creep instrument of the present invention, which includes an instrument table 108, a shear box, a pressurizing system and a dial indicator 102. Among them, a vertical baffle 101 is provided on the table top of the instrument table 108, and the table top of the instrument table is supported by four legs to maintain horizontality and is perpendicular to the vertical baffle. The table top has a through hole penetrating the table top.

[0029] The shear box is composed of a first box body 104, a second box body 103 and a pressure cover 106 to form a closed inner cavity for containing a soil sample 111. Figure 5 As shown, the first box body 104 is an annular shell with two open ends. The first box body is placed on the instrument table, and the left opening is connected to the opening of the second box body, and the right opening is closed by a pressure cover located on the steel hinge line.

[0030] The open end of the second box body is connected to the first box body, and the closed end opposite to the open end is provided with a pulley block 105 and a vertical baffle 101 in sliding contact. In order to keep the second box body smooth and avoid displacement when sliding vertically, a vertical track groove for sliding the pulley block can be further provided on the baffle. The first box body and the second box body are fixed together by an axial connecting bolt 114. When the connecting bolt is removed, the locking relationship between the first box body and the second box body is released, and the second box body can slide down relative to the first box body under the action of gravity. In order to prevent the sliding of the two from being displaced, matching vertical slide grooves and sliders can also be provided on the contact surfaces of the first box body and the second box body, respectively. Of course, the axial fixation between the first box body and the second box body can also be achieved by other means, such as providing matching limiting grooves and limiting edges, so that the two will not be axially separated.

[0031] The pressure cover extends to both sides to form extended ends, and each extended end is connected to a steel strand 107 .

[0032] The pressurization system includes a horizontal axial pressure weight system and a vertical shear force weight system. The horizontal axial pressure weight system includes a fixed pulley 112, a steel hinge 107, a first weight group 109 and a lever 113 mounted on the side of the instrument table. In this example, the lever 113 is a U-shaped lever composed of two longitudinal rods 113.1 and a cross bar 113.2 connected between the ends of the two longitudinal rods. The head end of the longitudinal rod 113.1 is hinged to the instrument table as the fulcrum of the lever. The first weight group 109 is suspended at the midpoint of the cross bar 113.2. The head end of the steel hinge is connected to the extended end of the pressure cover, and the end is connected to the rod body of the lever 113 after passing the fixed pulley 112. The length of the extended ends on both sides of the pressure cover is equivalent to the distance between the two inner fixed pulleys 105 of the baffle, and is greater than the width of the shear box body.

[0033] Of course, the present invention can also eliminate the lever and connect the first weight set directly to the end of the steel hinge wire.

[0034] The vertical shear force weight system includes a hanging rod 103.1 fixed to the lower surface of the second box body and passing through the through hole of the instrument table top, and a second weight group 110 hung at the bottom of the hanging rod.

[0035] The dial of the dial indicator 102 is fixedly connected to the baffle, and the spring contact head of the dial indicator contacts the top of the second box body.

[0036] The implementation steps of the present invention are as follows:

[0037] 1) Sample loading: Combine the first box body and the second box body, fix them with connecting bolts, load the soil sample, and cover with the pressure cover.

[0038] 2) Place the shear box: Place the shear box against the baffle and prepare to apply axial pressure.

[0039] 3) Apply axial pressure: Connect the pressure cover, steel strand, lever and the first weight group in sequence and apply axial pressure.

[0040] 4) Adjust the dial indicator: Fix the dial indicator on the baffle, make it contact with the second box body of the shear box, and adjust it to zero.

[0041] 5) Add shear force: hang the predetermined second weight set on the bottom hanging hole of the second box body hanging rod to provide shear force.

[0042] 6) Record: Record the shear deformation within the corresponding time according to the test requirements.

Claims

1. A vertical direct shear creep instrument, characterized in that include: Instrument table, shear box, dial indicator and pressurization system, The instrument table is provided with a vertical baffle, and the table near the vertical baffle has a through hole that runs through the table from top to bottom. The shear box is composed of a first box body and a second box body, and is used to hold the inner cavity of the soil sample. The first box body is an annular shell with two open ends. The first box body is placed on the instrument table so that one open end is connected to the opening of the second box body, and the other open end is closed by a pressure cover pulled by a steel hinge wire. The open end of the second box body is connected to the first box body, and the closed end opposite to the open end is provided with a pulley block and a vertical baffle plate for sliding contact. The vertical baffle plate is provided with a track groove for the pulley block to slide vertically. The dial of the dial indicator is relatively fixedly connected to the instrument table, and the spring contact head of the dial indicator contacts the top of the second box body. The pressurization system includes a horizontal axial pressure weight system and a vertical shear force weight system. The horizontal axial pressure weight system includes a fixed pulley mounted on the instrument table, a steel hinge wire that is fixedly connected to the pressure cover and then passes around the fixed pulley and hangs down, and a first weight group that is directly or indirectly connected to the hanging end of the steel hinge wire; the vertical shear force weight system includes a hanging rod that is fixed to the lower bottom surface of the second box body and passes through the perforated holes on the instrument table surface, and a second weight group that is hung at the bottom of the hanging rod; a detachable axial connecting bolt is provided between the first box body and the second box body. When the axial connecting bolt is removed, the second box body can slide down relative to the first box body under the action of force, and the second box body slides down relative to the first box body under the action of gravity and the second weight group.

2. The vertical direct shear creep instrument according to claim 1, characterized in that: The instrument table top is supported by four legs, kept horizontal, and perpendicular to the upright baffle.

3. The vertical direct shear creep instrument according to claim 1, characterized in that: The dial of the dial indicator is fixed on the upright baffle.

4. The vertical direct shear creep instrument according to claim 1, characterized in that: The contact surfaces of the first box body and the second box body are respectively provided with a vertical sliding groove and a sliding block for the second box body to slide vertically relative to the first box body and to adapt to each other.

5. The vertical direct shear creep instrument according to claim 1, characterized in that: The horizontal axial pressure weight system also includes a lever, the fulcrum of the lever is hinged to the side of the instrument table, the end of the steel hinge is fixedly connected to the lever body, and the first weight group is suspended at one end of the lever away from the fulcrum.

6. The vertical direct shear creep instrument according to claim 5, characterized in that: The lever is a U-shaped lever consisting of two longitudinal bars and a cross bar connected between the ends of the two longitudinal bars. The head end of the longitudinal bar is hinged to the side of the instrument table, and the first weight group is suspended in the middle of the cross bar.

7. The vertical direct shear creep instrument according to claim 6, characterized in that: The pressure cover extends to both sides to form extended ends, each extended end is connected to the head end of the steel strand on the same side, and the end of the steel strand is connected to the two longitudinal rod bodies of the lever.

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