US-20260125952-A1 - DEVICE AND ITS APPLICATION METHOD FOR IN-SITU CUTTING SOIL IN BOREHOLE

US20260125952A1US 20260125952 A1US20260125952 A1US 20260125952A1US-20260125952-A1

Abstract

The invention offers a device and method for in-situ cutting soil in boreholes. The device comprises a base with an accommodation cavity, a cutting mechanism attached to the base, featuring a driven driving part within the cavity and a cutting part at its opposite end. A telescopic drive mechanism atop the base connects to the cutting mechanism, facilitating its extension relative to the base along its length. A rotating drive mechanism at the base's bottom includes an active driving part within the cavity, rotating the cutting mechanism around its length axis. This enables the cutting part to slice soil along a plane perpendicular to its length extension. The device enables borehole tests to achieve a flat test surface, enhancing accuracy and effectiveness.

Inventors

Hengxing LAN
Changgen YAN
Mervyn LAN
Mingyu YANG
Han Bao
Wenbin LEI
Zhonghong DONG

Assignees

CHANG’AN UNIVERSITY

Dates

Publication Date: 20260507
Application Date: 20240222
Priority Date: 20230227

Claims (12)

1 . A device for in-situ cutting soil in borehole, wherein the device comprises: a base in which an accommodation cavity is arranged; a cutting mechanism, wherein the cutting mechanism is set to the base, the cutting mechanism includes a driven driving part arranged in the accommodation cavity and a cutting part located at the opposite end of the driven driving part; a telescopic drive mechanism, wherein the telescopic driving mechanism is arranged to the top of the base and connected to the cutting mechanism, which can drive the cutting mechanism to stretch relative to the base along its length extension direction; and a rotating drive mechanism, the rotating drive mechanism is set to the bottom of the base, the rotating driving mechanism includes an active driving part arranged in the accommodation cavity, the rotating drive mechanism is driven by the active driving part and the driven driving part to drive the cutting mechanism to rotate around the axis of its length extension direction, making the cutting part cut the soil along the plane of the axis perpendicular to the extension direction of the length.
2 . The device for in-situ cutting soil in borehole according to claim 1 , wherein the cutting mechanism also comprises a connecting mechanism arranged along the length extension direction of the cutting mechanism and located between the driven driving part and the cutting part, the connecting mechanism comprises a spline shaft fixedly connected to the driven part, the other end of the spline shaft can be movablely plugged into the axle sleeve, the other end of the axle sleeve is fixed to a cutterhead, a cutting tool for cutting soil is set on the cutterhead; wherein, when the spline shaft rotates under the drive of the rotating drive mechanism, the axle sleeve can rotate in linkage; when the telescopic drive mechanism drives the cutting mechanism to expand, the axle sleeve extends along the length extension direction relative to the spline shaft.
3 . The device for in-situ cutting soil in borehole according to claim 1 , wherein an end of the spline shaft inserted into the axle sleeve is constructed as a triangular column, a square column, a ladder column, a prism or a geometric column, and the corresponding end of the axle sleeve is provided with a shape matching insert; and/or the structure between the cutterhead and the cutting tool is a detachable connection, wherein, an embedded slot for detachable connection is set on the cutterhead, and the cutting tool is embedded on the cutterhead through the embedded slot; and/or the cutting tool includes a connecting part connected to the cutterhead and a sharp part convexly arranged on the cutterhead, the longitudinal section structure of the sharp part is a triangle.
4 . The device for in-situ cutting soil in borehole according to claim 3 , wherein the telescopic driving mechanism includes a guide plate of gear rack arranged to the top of the base, racks are installed on the guide plate of gear rack, the racks are meshed to a rotatable telescopic drive gear, the guide plate of gear rack can slide along the same expansion direction as the cutting mechanism under the drive of the expansion drive gear through the racks, the guide plate of gear rack is connected to a connecting pin extending to the cutting mechanism, the other end of the connecting pin is connected to an axle sleeve drive mechanism sleeved on the axle sleeve, wherein, the axle sleeve drive mechanism is constructed to drive the shaft sleeve to expand relative to the spline shaft but not rotate with the axle sleeve.
5 . The device for in-situ cutting soil in borehole according to claim 4 , wherein the axle sleeve drive mechanism comprises an axle sleeve fixed sleeve, the axle sleeve fixed sleeve is provided with a first convex ring extending inward along its radial direction on the inner surface of one side close to the driven part, the axle sleeve is provided with a second convex ring extending outward along its radial direction on the corresponding side; when the axle sleeve fixed sleeve is sleeved on the axle sleeve, the first convex ring is sleeved on the second convex ring; the axle fixed sleeve is embedded with an axle sleeve fixed ring connected to the sleeve on the inner surface outside the first convex ring, one end of the axle sleeve fixed ring is connected to the axial end surface of the first convex ring, the other end of the axle sleeve fixed ring is fixed by the first and second shield rings, the first shield ring is fixed to the axle sleeve fixed sleeve, the second shield ring is fixed to the sleeve; wherein, the inner surface of the axle sleeve fixed sleeve is provided with an annular first groove for fixing the first shield ring, the outer surface of the sleeve is provided with a second annular groove for fixing the second shield ring; a plug socket for connecting with the connecting pin is arranged on the axle sleeve fixed sleeve; and/or the top of the base is provided with a gear shaft connecting the telescopic drive gear and a gear shaft seat for fixing the gear shaft, the gear shaft runs through the gear shaft seat, the telescopic drive gear is connected to the gear shaft located below the gear shaft seat, and/or the top of the base is provided with a long strip connecting pin perforation for the connecting pin to pass through and move, and the connecting pin perforation extends along the sliding direction of the guide plate of gear rack.
6 . The device for in-situ cutting soil in borehole according to claim 5 , wherein a bottom surface of the gear shaft seat is attached to the guide plate of gear rack, the bottom of the gear shaft seat is provided with a gap extending to its circumference, the gap comprises at least an area above the connecting pin, which avoids interference between the connecting pin and the gear shaft seat, and/or the top of the base is provided with a groove for accommodating and installing the gear shaft seat, a chute is arranged in the groove to slide the rack guide plate, both ends of the chute extend to the outside of the base, when the rack guide plate is arranged in the groove, its side away from the telescopic drive gear fits on the side of the groove, wherein, the guide plate of gear rack is provided with a long strip-shaped rack slot for installing the rack along its sliding direction.
7 . The device for in-situ cutting soil in borehole according to claim 6 , wherein the device further comprises four groups of cutting mechanisms, the four groups of cutting mechanisms are extended or retracted at the same time with the same amount of expansion under the drive of the telescopic drive mechanism, and the four groups of cutting mechanisms rotate along the same rotation direction around the axis of the length extension direction under the drive of the rotating drive mechanism.
8 . The device for in-situ cutting soil in borehole according to claim 7 , wherein it further comprises four guide plates of gear rack, a first chute is arranged in the groove for sliding two guide plates of gear rack, both ends of the first chute extend to the outside of the base, a second chute is arranged in the groove for sliding the remaining two guide plates of gear rack, both ends of the second chute extend to the outside of the base, the bottom surface oft chute is higher than the bottom surface of the second chute and the first chute and the second chute are arranged alternately, it is preferred that the first chute and the second chute are perpendicular to each other, wherein the first chute or the two rack guide plates in the second chute are arranged side by side along the sliding direction of the guide plate of gear rack, and/or the guide plate of gear rack is constructed as a narrow part at one end and a wide part at the other end along its sliding direction, the wide part along the sliding direction perpendicular to the guide plate of gear rack is larger than that of the narrow part; wherein when the first chute or the two rack guide plates in the second chute are arranged, the wide part of one guide plate of gear rack fits the narrow part of the other guide plate of gear rack, the narrow part fits the wide part of the other guide plate of gear rack, and the middle of the two guide plates of gear rack is surrounded by a passage, so that four racks can be meshed simultaneously through one of the telescopic drive gears arranged in the passage.
9 . The device for in-situ cutting soil in borehole according to claim 8 , wherein a height of the device is 130-140 mm, and a width of the device is 140-150 mm, and/or an expansion amount of the cutting mechanism is 15-20 mm, wherein the wide part is provided with a perforation for connecting the connecting pin, the wide part is also provided with a step groove extending along the sliding direction of the guide plate of gear rack at the corner of the narrow part and close to the telescopic drive gear, which avoids the interference between the wide part and the rack.
10 . A method for in-situ cutting soil in borehole based on the device for in-situ cutting soil in borehole according to claim 7 , wherein the method comprises the following steps: putting the device into a prefabricated borehole until it reaches a predetermined position in the prefabricated borehole; the first motor starts and rotates forward, and the four groups of cutting mechanisms extend outward slowly at the same time with the same expansion amount until the outermost tool is embedded in the borehole wall soil of the prefabricated borehole, and the first motor stops working; the second motor starts and works, the four groups of cutting tools of the cutting mechanism cut the soil along the plane with the same rotation direction and rotation speed until the cutting soil is completed, and the second motor stops working; and the first motor starts and reverses again until the four groups of cutting mechanisms shrink back to the original position, the first motor stops working, and finally the device is taken out from the prefabricated borehole.
11 . A method for in-situ cutting soil in borehole based on the device for in-situ cutting soil in borehole according to claim 8 , wherein the method comprises the following steps: putting the device into a prefabricated borehole until it reaches a predetermined position in the prefabricated borehole; the first motor starts and rotates forward, and the four groups of cutting mechanisms extend outward slowly at the same time with the same expansion amount until the outermost tool is embedded in the borehole wall soil of the prefabricated borehole, and the first motor stops working; the second motor starts and works, the four groups of cutting tools of the cutting mechanism cut the soil along the plane with the same rotation direction and rotation speed until the cutting soil is completed, and the second motor stops working; and the first motor starts and reverses again until the four groups of cutting mechanisms shrink back to the original position, the first motor stops working, and finally the device is taken out from the prefabricated borehole.
12 . A method for in-situ cutting soil in borehole based on the device for in-situ cutting soil in borehole according to claim 9 , wherein the method comprises the following steps: putting the device into a prefabricated borehole until it reaches a predetermined position in the prefabricated borehole; the first motor starts and rotates forward, and the four groups of cutting mechanisms extend outward slowly at the same time with the same expansion amount until the outermost tool is embedded in the borehole wall soil of the prefabricated borehole, and the first motor stops working; the second motor starts and works, the four groups of cutting tools of the cutting mechanism cut the soil along the plane with the same rotation direction and rotation speed until the cutting soil is completed, and the second motor stops working; and the first motor starts and reverses again until the four groups of cutting mechanisms shrink back to the original position, the first motor stops working, and finally the device is taken out from the prefabricated borehole.

Description

TECHNICAL FIELD The present invention relates to the field of geotechnical engineering technology, in particular to a device and its application method for in-situ cutting soil in borehole. BACKGROUND ART The shear strength parameters of soil are the key index of engineering foundation design and the basis of building foundation stability analysis, which is related to the economy and safety of the whole project. At present, the shear strength parameters of soil are mainly obtained by indoor shear test or in-situ (or on-site) borehole shear test. The limitation of sample size in laboratory test leads to poor representativeness; the in-situ shear test is to apply an external load to the soil at the operating point, in the natural structure and stress environment of soil, the mechanical parameters of soil are obtained directly, which overcomes the shortcomings of soil disturbance and size effect in laboratory test, and the measured soil strength parameters are more accurate. Wherein, there are many kinds of soil, such as loess is a kind of collapsible soil, and the particle arrangement structure is quite different in the vertical direction and the horizontal direction. When rain falls, the loess slope will be collapsible by water, the structural strength is greatly reduced, resulting in a large area of landslide. Therefore, it is urgent to study the anisotropic permeability parameters of loess. In the process of realizing the invention, the inventors discover that there are at least the following problems in the prior art: The existing soil in-situ test devices, such as pressuremeter, plate load tester and flat dilatometer, have the following disadvantages: The pressuremeter: the pressuremeter includes three types: pre-drilling type, self-drilling type and pressing type, wherein the pressing type has obvious squeezing effect on the soil and is rarely used. The pre-drilling pressuremeter is represented by the French Mena pressuremeter, which needs to be drilled in advance, after considerable development, the product has realized the automation function(such as Geospad2 Mena pressuremeter, GeoPAC automatic control Mena pressuremeter, etc.), which includes automatic data acquisition, automatic execution of the test according to the set steps, independent elastic film constraint force and comprehensive deformation correction technology. The self-drilling pressuremeter is a one-time completion of drilling, pressuremeter equipment, positioning and testing, which has the characteristics of small disturbance to the soil of the borehole wall. Represented by the French PAF and British Camkometer pressuremeter in the 1970 s, after several generations of product updates, it has been digitized and automated, with flexible operation and high accuracy, and the obtained parameters do not require empirical correction. In terms of multifunctional pressuremeter: the third generation of French bridge type pressuremeter (PAF-76 type) probe can be replaced by other functional devices (such as shear instrument, permeameter and friction instrument, etc.), to achieve the purpose of multi-purpose borehole. In the late 1990 s, Xu Guangli and Qiantian Liangdao developed an in-situ shear combined pressuremeter, which can simultaneously measure mechanical parameters such as shear strength and deformation modulus, and then improved into a self-drilling in-situ shear pressuremeter. Flate dilatometer tester: one of the biggest characteristics of the flat dilatometer test is that it can provide the stress history information of the soil, Based on this, the influence of stress history can be well taken into account in the estimation of compression modulus of over-consolidated or under-consolidated soil. At present, the mainstream flat dilatometer equipment on the market includes two types: standard flat dilatometer tester (DMT) and seismic flat dilatometer tester (SDMT). The flat dilatometer test has the advantages of simple operation, continuous test, small disturbance, low cost and good repeatability, and it can be directly pressed into the soil by static penetration equipment or drilling rig. However, due to the small central membrane area of the flat shovel probe, when the soil particle composition contains a large number of stones, it is very easy to be unevenly stressed or difficult to penetrate, which is easy to cause large discreteness of test data or damage to the diaphragm. Therefore, the flat dilatometer test is not suitable for gravel soil or soil layer containing rubble, and the direction of soil force is inconsistent with the direction of actual soil load. The test results are based on statistical analysis and empirical formulas, and the results have regional attributes. Plate load tester: the plate load test is one of the earliest and most widely used soil test methods, it is an in-situ test to observe the pressure and deformation of natural foundation soil under various loads by applying loads on a certain size of rigid bearing