A soil shear strength in-situ testing device and testing method thereof

Abstract

The present invention discloses an in-situ testing device for the shear strength of soil and a testing method thereof, comprising a hollow large-diameter auger rod, a small-diameter auger rod and a drill rod pulling device, wherein the large-diameter auger rod and the small-diameter auger rod are arranged vertically coaxially and the small-diameter auger rod is installed in the hollow space of the large-diameter auger rod, and the drill rod pulling device comprises a support frame, a manual hoist installed on the support frame, and a hanging scale connected to the manual hoist. The advantages of the present invention are: the device is light, simple and convenient to operate, highly flexible and easy to move; it is suitable for testing reshaped soil samples, especially for testing original soil bodies in on-site construction; by setting two auger rods to rotate in the same direction, the small-diameter auger rod is taken out after the auger rods drill into the soil body to a certain extent, so as to avoid the soil in the large-diameter auger rod from squeezing to the surroundings to disturb the test soil body, and at the same time, to prevent the vacuum suction from being generated when the large-diameter auger rod is pulled out.

Description

Technical Field

[0001] The invention relates to the technical field of experimental testing equipment, in particular to an in-situ testing device for soil shear strength and a testing method thereof. Background Art

[0002] The shear strength of soil is determined through geotechnical tests. Common methods for indoor tests include direct shear test and triaxial shear test; however, these two shear strength test methods are only applicable to indoor reshaped soil sample tests and are not applicable to on-site in-situ soil tests. Currently, the methods for on-site in-situ tests include cross-plate shear test and large direct shear test; however, the cross-plate shear test is only applicable to on-site testing of the in-situ undrained shear strength of saturated soft clay, which has certain requirements for the soil; the large direct shear test equipment is heavy and inconvenient to carry.

[0003] Therefore, those skilled in the art are in urgent need of an in-situ testing device for soil shear strength that can solve the above problems. Summary of the invention

[0004] The purpose of the present invention is to provide an in-situ testing device and method for the shear strength of soil based on the above-mentioned deficiencies in the prior art, wherein a small-diameter auger rod is installed in the hollow space of a large-diameter auger rod, so that the small-diameter auger rod and the large-diameter auger rod rotate in the same direction and drill into the soil from top to bottom, and the large-diameter auger rod is pulled out using a manual hoist, thereby realizing the test of the shear strength of the soil.

[0005] The purpose of the present invention is achieved by the following technical solutions:

[0006] A soil shear strength in-situ testing device, characterized in that it includes a hollow large-diameter auger rod, a small-diameter auger rod and a drill rod pulling device, the large-diameter auger rod and the small-diameter auger rod are vertically coaxially arranged and the small-diameter auger rod is installed in the hollow space of the large-diameter auger rod, and the drill rod pulling device includes a support frame, a manual hoist installed on the support frame and a hanging scale connected to the manual hoist.

[0007] The large-diameter auger rod comprises a circular steel pipe, auger blades arranged on the outer wall of the circular steel pipe, and a large-diameter circular turntable arranged on the top of the circular steel pipe; the small-diameter auger rod comprises a circular iron rod, auger blades arranged on the outer wall of the circular iron rod, and a small-diameter circular turntable arranged on the top of the circular iron rod, the circular iron rod of the small-diameter auger rod passes through the large-diameter circular turntable of the large-diameter auger rod and extends to the inside of the circular steel pipe of the large-diameter auger rod, and the small-diameter circular turntable of the small-diameter auger rod is arranged above the large-diameter circular turntable of the large-diameter auger rod.

[0008] The spiral directions of the auger blades on the large-diameter auger rod and the small-diameter auger rod are the same, and the large-diameter auger rod and the small-diameter auger rod rotate in the same direction during operation.

[0009] The small-diameter spiral drill rod is provided with a strip buckle at the top end of its auger blade.

[0010] Inclined supports are provided between the large-diameter circular turntable and the circular steel pipe, and between the small-diameter circular turntable and the circular iron rod.

[0011] The hanging scale of the drill rod pulling device is connected to the large diameter spiral drill rod through a connecting hook

[0012] A testing method for an in-situ testing device for soil shear strength, characterized in that the testing method comprises the following steps:

[0013] a. Installing a small diameter auger rod in the hollow space of a large diameter auger rod, so that the small diameter auger rod and the large diameter auger rod rotate in the same direction and drill into the soil from top to bottom;

[0014] b. After the small-diameter auger rod and the large-diameter auger rod have drilled into the soil to a certain depth, the small-diameter auger rod is taken out upwards and the soil in the hollow space of the large-diameter auger rod is taken out;

[0015] c. Install a connecting hook on the large-diameter spiral drill rod, connect the connecting hook to the hanging scale of the drill rod pulling device, and reset the reading of the hanging scale to zero;

[0016] d. Start the manual hoist of the drill rod extraction device to extract the large-diameter auger rod from the soil, and record the maximum value reading of the hanging scale during the extraction of the large-diameter auger rod and the reading of the hanging scale when the large-diameter auger rod is completely extracted;

[0017] e. Calculate the shear strength of soil

[0018] .

[0019] The advantages of the present invention are:

[0020] 1. The device is light, easy to operate, convenient, flexible and easy to move; it is suitable for testing reshaped soil samples, especially for testing original soil bodies during on-site construction;

[0021] 2. By setting two auger rods to rotate in the same direction, the small diameter auger rod is taken out after the auger rod has penetrated into the soil to a certain extent, so as to avoid the soil in the large diameter auger rod from being squeezed to the surroundings and disturbing the test soil, and to prevent vacuum suction from being generated when the large diameter auger rod is pulled out; the soil shear strength test is achieved by pulling the large diameter auger rod upward. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the structure of a large diameter spiral drill rod and a small diameter spiral drill rod of the present invention;

[0023] Figure 2 It is a schematic diagram of the installation of the testing device of the present invention. DETAILED DESCRIPTION

[0024] The features of the present invention and other related features are further described in detail below through embodiments in conjunction with the accompanying drawings to facilitate understanding by those skilled in the art:

[0025] like Figure 1-2 As shown, the marks 1-12 in the figure respectively represent: a small diameter circular turntable 1, an inclined support 2, a bar buckle 3, a large diameter circular turntable 4, a screw dragon blade 5, a round iron rod 6, a round steel pipe 7, a hanging scale 8, a manual hoist 9, a connecting hook 10, a support frame 11, and a connecting bolt 12.

[0026] Example: Figure 1-2 As shown, the present embodiment relates to an in-situ testing device for the shear strength of soil, which mainly comprises a large-diameter auger rod, a small-diameter auger rod and a drill rod pulling device. The large-diameter auger rod is a hollow structure. The large-diameter auger rod and the small-diameter auger rod are coaxially arranged vertically, and the small-diameter auger rod is installed in the hollow space of the large-diameter auger rod, so that the small-diameter auger rod and the large-diameter auger rod rotate in the same direction and drill into the soil from top to bottom. After the small-diameter auger rod and the large-diameter auger rod drill into the soil to a certain depth, the small-diameter auger rod is taken out upwards and the soil in the hollow space of the large-diameter auger rod is taken out. The large-diameter auger rod is pulled out by the drill rod pulling device, and the shear strength of the soil can be tested.

[0027] like Figure 1-2 As shown, the large diameter auger rod comprises a circular steel pipe 7, an auger blade 5 and a large diameter circular turntable 4. The auger blade 5 is arranged on the outer wall of the circular steel pipe 7, and the large diameter circular turntable 4 is arranged on the top of the circular steel pipe 7. The large diameter auger rod can be drilled into the soil by rotating the large diameter circular turntable 4. In addition, an inclined support 2 is arranged between the large diameter circular turntable 4 and the circular steel pipe 7 to reinforce the connection between the large diameter circular turntable 4 and the circular steel pipe 7.

[0028] like Figure 1-2As shown, the small diameter auger rod comprises a round iron rod 6, an auger blade 5 and a small diameter round turntable 1. The auger blade 5 is arranged on the outer wall of the round iron rod 6, and the small diameter round turntable 1 is arranged on the top of the round iron rod 6. By rotating the small diameter round turntable 1, the small diameter auger rod can be drilled into the soil. The round iron rod 6 of the small diameter auger rod passes through the large diameter round turntable 4 of the large diameter auger rod and extends to the inside of the round steel pipe 7 of the large diameter auger rod. The small diameter round turntable 1 of the small diameter auger rod is arranged above the large diameter round turntable 4 of the large diameter auger rod. The auger blades 5 on the small diameter auger rod and the large diameter auger rod have the same spiral direction, and the small diameter auger rod and the large diameter auger rod rotate in the same direction when working. The small diameter auger rod is provided with a strip buckle 3 at the top of its auger blade 5, the size of the strip buckle 3 is larger than the inner diameter of the circular steel pipe 7 of the large diameter auger rod, and the strip buckle 3 cannot enter the circular steel pipe 7 of the large diameter auger rod. When working, the strip buckle 3 of the small diameter auger rod contacts the circular steel pipe 7 of the large diameter auger rod, which can ensure the stable operation of the small diameter auger rod in the large diameter auger rod. In addition, an oblique support 2 is provided between the small diameter circular turntable 1 and the circular iron rod 6 to reinforce the connection between the small diameter circular turntable 1 and the circular iron rod 6.

[0029] like Figure 1-2 As shown, the drill rod extraction device includes a support frame 11, a manual hoist 9 and a hanging scale 8. The support frame 11 can be assembled from multiple sections of square steel pipes for easy disassembly and transportation. The manual hoist 9 is installed on the support frame 11, and the hanging scale 8 is connected to the manual hoist 9. During operation, a connecting hook 10 can be installed on the large diameter circular turntable 4 of the large diameter spiral drill rod, and the connecting hook 10 is connected to the large diameter circular turntable 4 through a connecting bolt 12, so that the hanging scale 8 is hooked with the connecting hook 10, and the large diameter spiral drill rod in the soil can be pulled out through the manual hoist 9.

[0030] In addition, if Figure 1-2 As shown, this embodiment also has the following test method:

[0031] a. Install the small diameter auger rod in the circular steel pipe 7 of the large diameter auger rod, so that the small diameter auger rod and the large diameter auger rod rotate in the same direction and drill into the soil from top to bottom.

[0032] b. After the small-diameter auger rod and the large-diameter auger rod have drilled into the soil to a certain depth, the small-diameter auger rod is taken out upwards and the soil in the circular steel pipe 7 of the large-diameter auger rod is taken out, so as to avoid the soil in the large-diameter auger rod from squeezing around and disturbing the test soil, and at the same time prevent vacuum suction from being generated when the large-diameter auger rod is pulled out.

[0033] c. Install the connecting hook 10 on the large diameter circular turntable 4 of the large diameter spiral drill rod, connect the connecting hook 10 with the hanging scale 8 of the drill rod extraction device, and reset the reading of the hanging scale 8 to zero.

[0034] d. Start the manual hoist 9 of the drill rod extraction device to extract the large diameter auger rod from the soil, and record the maximum value reading of the hanging scale 8 during the extraction process of the large diameter auger rod and the reading of the hanging scale 8 when the large diameter auger rod is completely extracted.

[0035] e. Calculate the shear strength of soil

[0036] .

[0037] Although the above embodiments have described in detail the concepts and embodiments of the present invention with reference to the accompanying drawings, ordinary technicians in this field can recognize that various improvements and changes can still be made to the present invention without departing from the scope of the claims, so they are not described one by one here.

Claims

1. A testing method for an in-situ testing device for soil shear strength, characterized in that: The testing device comprises a hollow large-diameter auger rod, a small-diameter auger rod and a drill rod extraction device, wherein the large-diameter auger rod and the small-diameter auger rod are arranged vertically coaxially and the small-diameter auger rod is installed in the hollow space of the large-diameter auger rod, and the drill rod extraction device comprises a support frame, a manual hoist installed on the support frame, and a hanging scale connected to the manual hoist; The large-diameter auger rod comprises a circular steel pipe, an auger blade arranged on the outer wall of the circular steel pipe, and a large-diameter circular turntable arranged on the top of the circular steel pipe; the small-diameter auger rod comprises a circular iron rod, an auger blade arranged on the outer wall of the circular iron rod, and a small-diameter circular turntable arranged on the top of the circular iron rod, the circular iron rod of the small-diameter auger rod passes through the large-diameter circular turntable of the large-diameter auger rod and extends to the inside of the circular steel pipe of the large-diameter auger rod, and the small-diameter circular turntable of the small-diameter auger rod is arranged above the large-diameter circular turntable of the large-diameter auger rod; The testing method comprises the following steps: a. Installing a small diameter auger rod in the hollow space of a large diameter auger rod, so that the small diameter auger rod and the large diameter auger rod rotate in the same direction and drill into the soil from top to bottom; b. After the small-diameter auger rod and the large-diameter auger rod have drilled into the soil to a certain depth, the small-diameter auger rod is taken out upwards and the soil in the hollow space of the large-diameter auger rod is taken out; c. Install a connecting hook on the large-diameter spiral drill rod, connect the connecting hook to the hanging scale of the drill rod pulling device, and reset the reading of the hanging scale to zero; d. Start the manual hoist of the drill rod extraction device to extract the large-diameter auger rod from the soil, and record the maximum value reading of the hanging scale during the extraction of the large-diameter auger rod and the reading of the hanging scale when the large-diameter auger rod is completely extracted; e. Calculate the shear strength of soil 。 2. The testing method of the in-situ testing device for soil shear strength according to claim 1, characterized in that: The spiral directions of the auger blades on the large-diameter auger rod and the small-diameter auger rod are the same, and the large-diameter auger rod and the small-diameter auger rod rotate in the same direction during operation.

3. The testing method of the in-situ testing device for soil shear strength according to claim 1, characterized in that: The small-diameter spiral drill rod is provided with a strip buckle at the top end of its auger blade.

4. The testing method of the in-situ testing device for soil shear strength according to claim 1, characterized in that: Inclined supports are provided between the large-diameter circular turntable and the circular steel pipe, and between the small-diameter circular turntable and the circular iron rod.

5. The testing method of the in-situ testing device for soil shear strength according to claim 1, characterized in that: The hanging scale of the drill rod pulling device is connected with the large-diameter spiral drill rod through a connecting hook.

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