Weak surrounding rock tunnel soil pressure testing device

Abstract

The utility model provides a weak surrounding rock tunnel soil pressure testing device. The weak surrounding rock tunnel soil pressure testing device comprises a soil pressure box, a fixing assembly used for fixing the soil pressure box, a position adjusting assembly used for adjusting and controlling the position of a measuring face of the soil pressure box and a connecting assembly used for supporting the position adjusting assembly. The top surface of the soil pressure box is a measuring surface, and one side surface of the soil pressure box is provided with a cable interface; the fixing assembly comprises a supporting box body with an open top surface, and the earth pressure box is arranged in the supporting box body; the position adjusting assembly comprises an opposite-pull screw rod, an adjusting nut and a cross buckle, and the connecting assembly comprises a weldable hollow round pipe. According to the utility model, the installation position of the soil pressure box can be better adjusted, the problem that the soil pressure box is not tightly attached to surrounding rock during installation is solved, and the soil pressure box can be efficiently and conveniently buried in a weak surrounding rock tunnel; meanwhile, the soil pressure cell and the surrounding rock can be effectively prevented from disengaging or even falling off, the radial stress of the measuring face of the soil pressure cell is guaranteed, and therefore the survival rate of an instrument is guaranteed to a great extent, and the testing accuracy is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of underground space engineering, in particular to a soil pressure testing device for a soft surrounding rock tunnel. Background Art

[0002] In recent years, tunnel engineering, as an important part of transportation infrastructure, has ushered in a new stage of construction boom. Among them, clarifying the surrounding rock pressure of the tunnel is a prerequisite for the design of the tunnel support structure and an important premise for guiding on-site construction. The main methods for determining the surrounding rock pressure are: on-site field measurement method, theoretical formula calculation method, empirical method or engineering analogy method. Undoubtedly, on-site field measurement can directly obtain the surrounding rock pressure and is the most valuable engineering reference.

[0003] To directly measure the surrounding rock pressure on the supporting structure, the method of burying an earth pressure box behind the supporting structure is currently widely used. Admittedly, the surrounding rock pressure measured by this method is actually the contact stress between the surrounding rock and the supporting structure, and the measurement accuracy depends largely on the installation angle of the measuring surface of the earth pressure box and the degree of close contact with the surrounding rock. For mountain tunnels, the current common method of burying earth pressure boxes is to weld or tie the pressure box to the back of the tunnel steel arch frame, or drill holes in the surrounding rock to arrange expansion bolts, square wood chips or steel bars to fix the earth pressure box. However, for weak surrounding rock, the stratum is loose and broken, the degree of cementation is poor and the strength is low, and the drilled hole is prone to collapse, which is often difficult to serve as the force foundation of expansion bolts or steel bars. Direct installation of the earth pressure box is prone to detachment from the surrounding rock or even fall off. In addition, the construction of soft surrounding rock tunnels is prone to over-excavation, that is, a certain gap will be formed between the surrounding rock and the supporting structure, which may reach tens of centimeters in severe cases. Therefore, in this case, it is difficult for the earth pressure box to be installed on the back of the tunnel steel arch frame to be close to the surrounding rock, which will greatly affect the measurement results. In response to this situation, a few solutions currently use other materials such as steel bars and square timber to raise the earth pressure box or fill the pores with concrete, gypsum, anchors, hot melt adhesives, etc. However, since the amount of over-excavation in different parts of the on-site tunnel construction is not the same, these methods are not convenient for adjusting the position of the earth pressure box and will affect the force transfer between the surrounding rock and the support. Utility Model Content

[0004] The purpose of the utility model is to provide a device for testing the earth pressure of a tunnel with soft surrounding rock, which is convenient for adjusting the position of the earth pressure box and does not affect the force transmission between the surrounding rock and the support, in view of the shortcomings existing in the above-mentioned background technology.

[0005] In order to achieve the above-mentioned object, the utility model provides a soil pressure testing device for a soft surrounding rock tunnel, comprising a soil pressure box, a fixing assembly for fixing the soil pressure box, a positioning assembly for adjusting the position of the measuring surface of the soil pressure box, and a connecting assembly for supporting the positioning assembly;

[0006] The top surface of the earth pressure box is the measuring surface, and a cable interface is provided on one side of the earth pressure box to connect a cable;

[0007] The fixing assembly comprises a support box body with an open top surface, and the earth pressure box is arranged in the support box body;

[0008] The positioning assembly includes a tension screw, an adjusting nut and a cross buckle, and the connecting assembly includes a weldable hollow circular tube; the cross buckle is fixedly connected to the support box body, the cross buckle is provided with a center nut, the tension screw is provided with an external thread, the first end of the tension screw is threadedly matched with the center nut, the adjusting nut is sleeved on the tension screw and threadedly matched, the weldable hollow circular tube is inserted from the second end of the tension screw and supports the tension screw, and the weldable hollow circular tube is welded to the tunnel steel arch frame.

[0009] Furthermore, the soil pressure box is configured to be in a round cake shape, the support box body is configured to be in a rectangular shape, the side length of the support box body is greater than the outer diameter of the soil pressure box, threaded holes are provided on three sides of the support box body and adjusting bolts are inserted therein, and a wire threading groove is provided on the fourth side, the adjusting bolt is used to clamp and fix the soil pressure box, and the cable interface passes through the wire threading groove.

[0010] Furthermore, the gap between the earth pressure box and the support box body is filled with a flexible material.

[0011] Furthermore, the cross buckle also includes a plurality of side ribs, and the side ribs and the center nut are configured as an integral structure, and the side ribs and the center nut are both fixed to the lower surface of the support box body.

[0012] Furthermore, the adjusting nut is configured to be butterfly-shaped.

[0013] Furthermore, the tension screw is a solid threaded round steel.

[0014] Furthermore, the measuring surface of the earth pressure box is fitted to the surrounding rock and is pressed tightly under the thread force of the tension screw.

[0015] The above solution of the utility model has the following beneficial effects:

[0016] The earth pressure test device for a soft rock tunnel provided by the utility model can better adjust the installation position of the earth pressure box through the arrangement of the fixing component, the adjusting component and the connecting component, overcome the problem that the earth pressure box is not closely attached to the surrounding rock during installation in a soft rock tunnel, especially in the case of over-excavation during construction, and realize efficient and convenient burying of the earth pressure box in a soft rock tunnel; at the same time, it can effectively avoid the earth pressure box from being emptied or even falling off from the surrounding rock, ensure the radial force on the measuring surface of the earth pressure box, thereby largely ensuring the survival rate of the instrument and improving the test accuracy;

[0017] Other beneficial effects of the present invention will be described in detail in the subsequent specific implementation sections. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0019] Figure 2 It is a schematic diagram of the fixing assembly of the utility model;

[0020] Figure 3 It is a schematic diagram of a cross buckle of the utility model;

[0021] Figure 4 It is a schematic diagram of the adjusting nut and the tension screw rod of the utility model.

[0022] [Description of Reference Numerals]

[0023] 10-soil pressure box; 11-measuring surface; 12-cable interface; 20-fixing assembly; 21-support box body; 22-adjusting bolt; 23-wire groove; 30-positioning assembly; 31-tension screw; 32-adjusting nut; 33-cross buckle; 331-center nut; 332-side rib; 40-connecting assembly; 50-tunnel steel arch frame. DETAILED DESCRIPTION

[0024] In order to facilitate the understanding of the present application, the present application will be described more comprehensively with reference to the relevant drawings below. The preferred embodiments of the present application are provided in the drawings. However, the present application can be implemented in many other different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0025] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0026] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0027] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0028] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0029] like Figure 1 As shown, an embodiment of the utility model provides an earth pressure testing device for a soft surrounding rock tunnel, comprising an earth pressure box 10, a fixing assembly 20 for fixing the earth pressure box 10, an adjusting assembly 30 for adjusting the position of the measuring surface of the earth pressure box 10, and a connecting assembly 40 for supporting the adjusting assembly 30.

[0030] At the same time Figure 2 As shown, the earth pressure box 10 is set in a round pancake shape, the top surface of the earth pressure box 10 is a measuring surface 11, and a cable interface 12 is set on one side of the earth pressure box 10 for connecting the cable. The fixing assembly 20 includes a support box body 21 with an open top surface, and the support box body 21 is used to accommodate and support the earth pressure box 10, and its side length is greater than the outer diameter of the earth pressure box 10. Threaded holes are set on three sides of the support box body 21 and adjustment bolts 22 are inserted, and a threading groove 23 is set on the fourth side. The earth pressure box 10 is clamped and fixed by the adjustment bolt 22, and the cable interface 12 is passed through the threading groove 23.

[0031] It should be noted that the earth pressure box 10 is conventionally in the shape of a round pancake, and the support box body 21 is set to be square for the convenience of setting the adjustment bolts 22. In other embodiments, a circular shape or other shapes may also be considered, and no specific limitation is made here.

[0032] It should be noted that when the earth pressure box 10 is installed, its measuring surface 11 needs to be slightly higher than the upper edge of the supporting box body 21, and the gap between the earth pressure box 10 and the supporting box body 21 is filled with flexible materials such as foam or sealant to keep the earth pressure box 10 stable during measurement. During specific installation, first put the measuring surface 11 of the earth pressure box 10 upward into the supporting box body 21, embed the cable interface 12 into the threading groove 23, and then gradually tighten the adjustment bolts 22 on the three sides to fix the earth pressure box 10 to the fixing assembly 20. Then, fill the gap with flexible materials such as foam or sealant to ensure that only the measuring surface 11 of the earth pressure box 10 and the cable interface 12 are exposed.

[0033] In this embodiment, the positioning assembly 30 includes a tensioning screw 31, an adjusting nut 32 and a cross buckle 33. The first end of the tensioning screw 31 is fixedly connected to the cross buckle 33 (welded or integrally arranged), and the second end of the tensioning screw 31 is connected to the tunnel steel arch 50 through the coupling assembly 40. Figure 3 As shown, in this embodiment, the cross buckle 33 includes a central nut 331 and four side ribs 332, all of which are fixed (through welding, etc.) to the bottom surface of the support box body 21. The side ribs 332 improve the connection stability. Of course, the number of side ribs is not limited to four, and can also be three or other numbers. Figure 4 As shown, the tension screw 31 is a solid threaded round steel, which matches the central nut 331 and the adjusting nut 32. The adjusting nut 32 itself is set to be butterfly-shaped for easy manual adjustment. The connecting assembly 40 includes a weldable hollow circular tube with a diameter slightly larger than the tension screw. When welded to the tunnel steel arch frame 50, the welding direction is along the radial direction of the tunnel steel arch frame 50.

[0034] During the specific installation, the first end of the tension screw 31 is inserted into the center nut 331 of the cross buckle 33, and after tightening, the adjusting nut 32 is inserted into the tension screw 31, and then the weldable hollow circular tube is inserted from the second end of the tension screw 31, and the length of the tension screw 31 passing through the weldable hollow circular tube is adjusted by rotating the adjusting nut 32 to adjust the position of the support box body 21 and the earth pressure box 10 connected to the tension screw 31, until the measuring surface 11 of the earth pressure box 10 fits with the surrounding rock, and a firm state is formed under the joint action of the thread force and the reaction force. It should be noted that the weldable hollow circular tube can play a connecting role as well as a protective sleeve to ensure that the tension screw 31 will not be damaged during the radial welding of the weldable hollow circular tube along the tunnel steel arch frame 50.

[0035] As described above, the earth pressure testing device for a tunnel with soft surrounding rock provided in this embodiment can better adjust the installation position of the earth pressure box 10 through the arrangement of the fixing assembly 20, the adjusting assembly 30 and the connecting assembly 40, overcome the problem of the earth pressure box 10 not being closely attached to the surrounding rock when installed in a tunnel with soft surrounding rock, especially in the case of over-excavation during construction, and realize efficient and convenient burial of the earth pressure box 10 in the tunnel with soft surrounding rock; at the same time, it can effectively avoid the earth pressure box 10 from being emptied or even falling off from the surrounding rock, and ensure that the measuring surface 11 of the earth pressure box 10 is subjected to radial force, thereby ensuring the survival rate of the instrument to a great extent and improving the test accuracy.

[0036] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0037] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A soil pressure test device for soft surrounding rock tunnels, characterized in that: It comprises an earth pressure box (10), a fixing assembly (20) for fixing the earth pressure box (10), a positioning assembly (30) for adjusting the position of a measuring surface (11) of the earth pressure box (10), and a connecting assembly (40) for supporting the positioning assembly (30); The top surface of the earth pressure box (10) is the measuring surface (11), and a cable interface (12) is provided on one side of the earth pressure box (10); The fixing assembly (20) comprises a support box body (21) with an open top surface, and the earth pressure box (10) is arranged in the support box body (21); The positioning assembly (30) includes a tension screw (31), an adjusting nut (32) and a cross buckle (33), and the connecting assembly (40) includes a weldable hollow circular tube; the cross buckle (33) is fixedly connected to the support box body (21), and the cross buckle (33) is provided with a central nut (331). The tension screw (31) is provided with an external thread, and the first end of the tension screw (31) is threadedly matched with the central nut (331). The adjusting nut (32) is sleeved on the tension screw (31) and threadedly matched. The weldable hollow circular tube is inserted from the second end of the tension screw (31) and supports the tension screw (31), and the weldable hollow circular tube is welded to the tunnel steel arch frame (50).

2. The soil pressure testing device for soft surrounding rock tunnel according to claim 1 is characterized in that: The earth pressure box (10) is arranged in a round cake shape, the support box body (21) is arranged in a rectangular shape, the side length of the support box body (21) is greater than the outer diameter of the earth pressure box (10), three side surfaces of the support box body (21) are provided with threaded holes and are provided with adjusting bolts (22), and the fourth side surface is provided with a threading groove (23), the adjusting bolts (22) are used to clamp and fix the earth pressure box (10), and the cable interface (12) is passed through the threading groove (23).

3. The soil pressure testing device for soft surrounding rock tunnel according to claim 2 is characterized in that: The gap between the earth pressure box (10) and the support box body (21) is filled with flexible material.

4. The soil pressure testing device for soft surrounding rock tunnel according to claim 1 is characterized in that: The cross buckle (33) further comprises a plurality of side ribs (332), wherein the side ribs (332) and the central nut (331) are arranged as an integral structure, and the side ribs (332) and the central nut (331) are both fixed on the lower surface of the supporting box body (21).

5. The soil pressure testing device for soft surrounding rock tunnel according to claim 1 is characterized in that: The adjusting nut (32) is configured in a butterfly shape.

6. The soil pressure testing device for soft surrounding rock tunnel according to claim 1 is characterized in that: The tension screw rod (31) is a solid threaded round steel bar.

7. A soil pressure testing device for soft surrounding rock tunnel according to any one of claims 1 to 6, characterized in that: The measuring surface (11) of the earth pressure box (10) fits the surrounding rock and is pressed tightly under the action of the thread force of the tension screw (31).

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