A device for testing the toughness of mud cake in underground engineering.

Abstract

This invention relates to a device for testing the toughness of mud cake in underground engineering, comprising a support, a vertically movable bracket, and a mud cake placement frame. The support has a vertically movable bracket, and the mud cake placement frame is fixedly mounted on the bracket. A surrounding measuring mechanism for measuring mud cake thickness and fracture is provided on the outer side of the mud cake placement frame. A folding plate is located at the bottom of the mud cake placement frame and inside the frame body. A second vertical ruler is located at the lower center of the folding plate. A suspension for fixing the second vertical ruler is located below the mud cake placement frame. The second vertical ruler is inserted into the suspension. A lifting drive mechanism for driving the second vertical ruler upward or downward is provided on one side of the suspension. This invention can more conveniently and accurately measure the circumferential thickness of the mud cake, more accurately record the bending angle after the mud cake breaks, as well as the bending angle and maximum fracture width after complete fracture, and effectively characterize the quality of the mud cake based on accurate measurements.

Description

Technical Field

[0001] This invention belongs to the field of mud cake performance testing technology, specifically relating to a device for testing the toughness of mud cake in underground engineering slurry. Background Technology

[0002] Drilling mud plays a crucial role in the construction of underground engineering projects such as diaphragm walls, pipe jacking, tunnel boring machines, and bored piles, serving as the "lifeblood" of underground engineering. Common performance indicators for drilling mud include viscosity, specific gravity, and sand content. Among these, the quality of the mud cake is key to determining the overall quality of the drilling mud. A high-quality mud cake allows the hydrostatic pressure of the mud to effectively act on the trench wall, preventing borehole collapse and providing protection. A high-quality mud cake is characterized by its thinness, density, and toughness, along with high cohesion, which helps maintain the stability of the borehole and trench walls and prevent collapse. Traditional mud cake testing methods involve measuring mud loss using a mud loss meter and then using calipers to determine the mud cake thickness. This method offers limited and effective characterization of mud cake performance. For example, it fails to fully characterize the mud cake's properties, such as the tendency for it to fracture after bending at a certain angle and the degree of fracture at different angles. These characteristics are crucial for assessing mud cake performance. To address these issues, we propose a mud cake toughness testing device for underground engineering drilling mud. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of existing technologies that rely on a single testing indicator, and to propose a device for testing the toughness of mud skin in underground engineering.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A device for testing the toughness of mud cake in underground engineering includes a support, a vertically movable bracket, and a mud cake placement frame. The support is equipped with the vertically movable bracket, and the mud cake placement frame is fixedly mounted on the bracket. A surrounding measuring mechanism for measuring mud cake thickness and mud cake fracture is provided on the outer side of the mud cake placement frame. A folding plate is provided at the bottom of the mud cake placement frame and on the inner side of the frame. A second vertical ruler is provided at the lower center of the folding plate. A suspension for fixing the second vertical ruler is provided below the mud cake placement frame. The second vertical ruler is inserted into the suspension. A lifting drive mechanism for driving the second vertical ruler to move up or down is provided on one side of the suspension.

[0006] Furthermore, a locking bolt is provided on one side of the bracket corresponding to the support.

[0007] Furthermore, the surrounding measuring mechanism includes an annular slide rail, an annular slider, and a first vertical ruler. The annular slide rail is fixed to the outside of the mud skin placement frame. An annular slider is slidably connected to the annular slide rail. A first vertical ruler is provided on the annular slider. A marker is slidably connected to the first vertical ruler. A contact post is provided on one side of the marker corresponding to the mud skin placement frame.

[0008] Furthermore, a balance scale is provided on one side of the bottom of the contact post.

[0009] Furthermore, when the slider is located at the bottom of the first vertical ruler, the bottom of the contact post contacts the folding plate.

[0010] Furthermore, the width of the folding plate is the same as the width of the second vertical ruler.

[0011] Furthermore, the folding plate is an elastic rubber plate, with both ends of the elastic rubber plate fixed to the bottom sides of the mud placement frame, and the middle part of the elastic rubber plate fixedly connected to the top of the second vertical ruler.

[0012] Furthermore, the folding plate consists of two symmetrical rigid plates. The bottom sides of the mud placement frame are provided with corresponding lugs at the ends. The lugs on the same side are rotatably connected to a rotating rod. The rigid plate is installed through the rotating rod. One end of the rigid plate inside the mud placement frame is rotatably connected to the end of the second vertical ruler.

[0013] Furthermore, the lifting drive mechanism includes a rack and a housing. A rotating shaft is provided inside the housing. The rack is fixed on both sides of the second vertical ruler. A gear that meshes with the rack is fixed on the rotating shaft. A worm gear is fixed on one end of the rotating shaft. A matching worm is connected to the worm gear. A handle is fixed on the bottom of the worm gear.

[0014] The beneficial effects of this invention are as follows:

[0015] This invention allows for more convenient and accurate measurement of the circumferential thickness of the mud skin, more accurate recording of the bending angle after the mud skin breaks, the bending depth after complete breakage, and the maximum fracture width. Accurate measurements can effectively characterize the quality of the mud skin. Specifically:

[0016] The system uses a surround measuring mechanism to detect the thickness and fracture width of the mud skin from all angles. It can also fold the mud skin and accurately record the scales at which the mud skin fractures and completely fractures, based on the folding progress scale displayed on the second vertical ruler. The corresponding folding angle is calculated, and the size of the crack in the mud skin is measured using a balance ruler. Attached Figure Description

[0017] Figure 1 This is a three-dimensional structural schematic diagram of the underground engineering mud and mud skin toughness testing device of the present invention;

[0018] Figure 2 This is a side view of the underground engineering mud and mud skin toughness testing device of the present invention;

[0019] Figure 3 This is a schematic diagram of the internal structure of the lifting drive mechanism in this invention;

[0020] Figure 4 This is a schematic diagram of the mud skin placement frame and its internal structure in Example 1;

[0021] Figure 5 This is a schematic diagram of the mud skin folding process in Example 1;

[0022] Figure 6 This is a schematic diagram of the mud skin placement frame and its internal structure in Example 2;

[0023] Figure 7 This is a schematic diagram of the mud folding process in Example 2;

[0024] The markings in the diagram are as follows: 1. Support; 2. Bracket; 3. Locking bolt; 4. Mud pad placement frame; 41. Support lug; 42. Rotating rod; 5. Folding plate; 6. Circular slide rail; 61. Circular slider; 7. First vertical ruler; 8. Sliding marker; 9. Contact column; 10. Suspension; 11. Second vertical ruler; 111. Rack; 12. Lifting drive mechanism; 120. Housing; 121. Rotating shaft; 122. Gear; 123. Turbine; 124. Worm gear; 125. Handle. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0026] The structural features of the present invention will now be described in detail with reference to the accompanying drawings.

[0027] Example 1: See Figures 1 to 5 A device for testing the toughness of mud skin in underground engineering includes a support 1, a support 2 that can move up and down on the support 1, a locking bolt 3 on one side of the support 2 corresponding to the support 1, the support 2 can be fixed on the support 1 by the locking bolt 3, a mud skin placement frame 4 is fixed on the support 2, the mud skin placement frame 4 has a square structure to facilitate the folding and measurement of mud skin, and a surrounding measuring mechanism for measuring mud skin thickness and mud skin fracture is provided on the outside of the mud skin placement frame 4.

[0028] The surrounding measuring mechanism includes an annular slide rail 6, which is fixed to the outside of the mud skin placement frame 4. An annular slider 61 is slidably connected to the annular slide rail 6, and a first vertical ruler 7 is fixedly mounted on the annular slider 61. A slider 8 is slidably connected to the first vertical ruler 7, and a contact post 9 is provided on one side of the slider 8 corresponding to the mud skin placement frame 4. When the slider 8 is at the bottom of the first vertical ruler 7, the bottom of the contact post 9 contacts the folding plate 5. The annular slider 61 can slide around the annular slide rail 6, so that the first vertical ruler 7 can be moved to any position in the circumference of the mud skin. By moving the slider 8, the bottom of the contact post 9 contacts the upper surface of the mud skin. At this time, the scale of the slider 8 corresponding to the first vertical ruler 7 is the thickness of the mud skin at the position of the first vertical ruler 7. A balance scale 91 is provided on one side of the bottom of the contact post 9. The balance scale 91 is used to measure the width of the crack when the mud skin breaks.

[0029] A folding plate 5 is provided at the bottom of the mud-skin placement frame 4 and on the inner side of the frame. A second vertical ruler 11 is fixedly installed at the lower center of the folding plate 5. The width of the folding plate 5 is the same as the width of the second vertical ruler 11. The folding plate 5 is an elastic rubber plate 51. The two ends of the elastic rubber plate 51 are fixed to the bottom sides of the mud-skin placement frame 4. The middle part of the elastic rubber plate 51 is fixedly connected to the top of the second vertical ruler 11. When the second vertical ruler 11 lifts the middle part of the elastic rubber plate 51, the middle part of the elastic rubber plate 51 will arch upward. The lifting distance of the second vertical ruler 11 can be converted into the angle of mud folding at this time using the Pythagorean theorem. When cracks appear in the mud folding, the scale of the second vertical ruler 11 is recorded at this time. When the mud folding is completely cracked, the scale of the second vertical ruler 11 is recorded again. The folding angle of mud when the mud breaks and when it is completely broken can be calculated by the two recorded scales. After the mud is completely broken, the width of the crack is measured using a balance ruler 91, and the width of the maximum fold crack of the mud is recorded. Below the mud-skin placement frame 4 is a suspension 10 for fixing the second vertical ruler 11. The second vertical ruler 11 is inserted into the suspension 10. A lifting drive mechanism 12 for driving the second vertical ruler 11 to move upwards or downwards is provided on one side of the suspension 10. The lifting drive mechanism 12 includes a rack 111 and a housing 120. A rotating shaft 121 is provided inside the housing 120. The rack 111 is fixed to both sides of the second vertical ruler 11. A gear 122 that meshes with the rack 111 is fixed to the rotating shaft 121. A turbine 123 is fixed to one end of the rotating shaft 121. A suitable worm gear 124 is connected to the top, and a handle 125 is fixedly provided at the bottom of the worm gear 124. By turning the handle 125, the rotating shaft 121 is driven to rotate under the transmission of the worm gear 123 and the worm gear 124. Then, the gear 122 on the rotating shaft 121 drives the rack 111 to move the second vertical ruler 11 up and down. By raising the second vertical ruler 11, the elastic rubber plate 51 is arched upward, thereby folding the mud in the mud placement frame 4. After the mud is placed in the mud placement frame 4, the two sides of the mud need to be temporarily fixed by clamps.

[0030] The underground engineering mud cake toughness testing device of the present invention has a simple structure, is easy to operate, and can accurately measure and effectively characterize the performance of mud cake. On the one hand, it can more conveniently and accurately measure the circumferential thickness of mud cake; on the other hand, during use, it can accurately record the bending angle after the mud cake breaks, as well as the bending angle and maximum fracture width after complete fracture.

[0031] Specifically, in use, the prepared rectangular clay sheet is placed in the clay sheet placement frame 4 and fixed on both sides with clamps. Multiple thickness values ​​are measured on the circumference of the clay sheet using the first vertical ruler 7. Then, the clay sheet is folded by raising the second vertical ruler 11 until a crack appears at the fold. Folding is stopped at this point, and the scale of the second vertical ruler 11 is recorded. The second vertical ruler 11 is then raised again. During this process, the crack in the clay sheet continuously increases. After each small distance of raising, the width of the crack is measured and recorded using the balance ruler 91 until the clay sheet breaks completely at the bend. At this point, the maximum width of the break is recorded, along with the corresponding scale value of the second vertical ruler 11. The folding angle and the relationship between the folding angle and the crack width are calculated from the recorded values ​​of the second vertical ruler 11, thus characterizing the performance of the clay sheet.

[0032] Example 2:

[0033] Reference Figure 6 , Figure 7 In another preferred embodiment of the present invention, the difference from Embodiment 1 is that the folding plate 5 consists of two symmetrical rigid plates 52. Corresponding lugs 41 are provided at the ends of both sides of the bottom of the mud-skin placement frame 4. A rotating rod 42 is rotatably connected to the lug 41 on the same side. The rigid plate 52 is disposed through the rotating rod 42, and one end of the rigid plate 52 located inside the mud-skin placement frame 4 is rotatably connected to the end of the second vertical ruler 11. The folding angle of the mud-skin is detected using bidirectionally symmetrical rigid plates 52.

[0034] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A device for testing the toughness of mud cake in underground engineering, characterized in that: The device includes a support (1), a vertically movable bracket (2), and a mud-skin placement frame (4). The support (1) is equipped with the vertically movable bracket (2), and the mud-skin placement frame (4) is fixedly mounted on the bracket (2). The outer side of the mud-skin placement frame (4) is equipped with a surrounding measuring mechanism for measuring mud-skin thickness and mud-skin breakage. The bottom of the mud-skin placement frame (4) and the inner side of the frame are equipped with a folding plate (5). The lower center of the folding plate (5) is equipped with a second vertical ruler (11). The lower part of the mud-skin placement frame (4) is equipped with a suspension (10) for fixing the second vertical ruler (11). The second vertical ruler (11) is inserted into the suspension (10). One side of the suspension (10) is equipped with a mechanism for driving the second vertical ruler. The lifting drive mechanism (12) for the ruler (11) to move up or down; the surrounding measuring mechanism includes an annular slide rail (6), an annular slider (61), and a first vertical ruler (7). The annular slide rail (6) is fixed to the outside of the mud skin placement frame (4). An annular slider (61) is slidably connected to the annular slide rail (6). A first vertical ruler (7) is provided on the annular slider (61). A slider (8) is slidably connected to the first vertical ruler (7). A touch post (9) is provided on one side of the mud skin placement frame (4) corresponding to the slider (8). A balance scale (91) is provided on one side of the bottom of the touch post (9). When the slider (8) is located at the bottom of the first vertical ruler (7), the bottom of the touch post (9) is in contact with the folding plate (5).

2. The underground engineering mud cake toughness testing device according to claim 1, characterized in that: The bracket (2) is provided with a locking bolt (3) on one side corresponding to the support (1).

3. The underground engineering mud cake toughness testing device according to claim 1, characterized in that: The width of the folding plate (5) is the same as the width of the second vertical ruler (11).

4. The underground engineering mud cake toughness testing device according to claim 1, characterized in that: The folding plate (5) is an elastic rubber plate (51). The two ends of the elastic rubber plate (51) are fixed to the bottom sides of the mud skin placement frame (4), and the middle part of the elastic rubber plate (51) is fixedly connected to the top of the second vertical ruler (11).

5. The underground engineering mud cake toughness testing device according to claim 1, characterized in that: The folding plate (5) consists of two symmetrical hard plates (52). The bottom sides of the mud placement frame (4) are provided with corresponding lugs (41) at the ends. The lugs (41) on the same side are rotatably connected to a rotating rod (42). The hard plate (52) is installed through the rotating rod (42). One end of the hard plate (52) located inside the mud placement frame (4) is rotatably connected to the end of the second vertical ruler (11).

6. The underground engineering mud cake toughness testing device according to claim 1, characterized in that: The lifting drive mechanism (12) includes a rack (111) and a housing (120). A rotating shaft (121) is provided inside the housing (120). The rack (111) is fixed on both sides of the second vertical ruler (11). A gear (122) that meshes with the rack (111) is fixed on the rotating shaft (121). A turbine (123) is fixed at one end of the rotating shaft (121). A matching worm gear (124) is connected to the turbine gear (123). A handle (125) is fixed at the bottom of the worm gear (124).

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