A method and device for actively controlling large deformation of deep thin-layered surrounding rock

Abstract

The present invention discloses a method and device for actively controlling large deformation of thin-layered surrounding rock in deep areas. The active control method comprises: drilling a hole in the tunnel surrounding rock close to the face, and then adding an active control device containing a sleeve, a high-strength prestressed anchor rod, a resin anchoring agent and a grouting device into the hole, applying a pre-tightening force to the anchor rod after the resin anchoring agent has a certain strength, and performing delayed grouting on the surrounding rock through the grouting device after the stress adjustment is completed, wherein the high-strength prestressed anchor rod and the grouting device are inserted into a sleeve with holes on the side. The active control device or method of the present invention can effectively reduce the depth and degree of rupture of thin-layered soft rock in deep engineering, and effectively suppress the occurrence of large deformation disasters.

Description

Technical Field

[0001] The invention belongs to the technical field of geotechnical engineering, and particularly relates to the technical field of a method for controlling large deformation of surrounding rocks. Background Art

[0002] For deep thin-layered rock projects, due to the high ground stress level, after tunnel excavation, the surrounding rock will produce large-scale inter-layer fractures in a short period of time, resulting in large deformation disasters of level M, which will seriously damage the support structure, threaten the safety of construction workers, affect the progress of the project, and cause great economic losses.

[0003] As an efficient support method, anchor support has been widely used in the field of surrounding rock support. However, in the practice of controlling deep thin-layered surrounding rock, ordinary mortar anchors may cause large-scale rupture of the surrounding rock due to untimely anchoring force, the anchors may be pulled off due to large deformation of the surrounding rock, the anchors may be sheared off due to shear slip along the layers of the surrounding rock, and the rock mass may continue to crack due to the long stress adjustment time of the surrounding rock. To solve the above problems, it is necessary to develop new active control methods and devices for large deformation of deep thin-layered surrounding rock. Summary of the invention

[0004] In view of the problems in the prior art of controlling large deformation of deep thin-layered surrounding rock such as high-stress tunnel thin-layered surrounding rock, such as poor timeliness of support means, easy breaking or shearing of anchor rods, and poor integrity of surrounding rock after stress adjustment, the purpose of the present invention is to propose a new active control method and device for large deformation of deep thin-layered surrounding rock.

[0005] The technical solution of the present invention is as follows:

[0006] A device for actively controlling large deformation of thin-layered surrounding rock in deep parts, comprising: a sleeve with holes on both sides, a high-strength prestressed anchor rod inserted in the sleeve and extending outside the sleeve, and a grouting device arranged side by side with the anchor rod and capable of grouting operation; a reverse anti-skid device is provided at the tail end of the high-strength prestressed anchor rod extending into the thin-layered surrounding rock in deep parts through a construction hole, and a resin anchor filling section formed by an applied resin anchoring agent located at the front end of the reverse anti-skid device and between the high-strength prestressed anchor rod and the sleeve, wherein the reverse anti-skid device is a resin anchoring agent that can be fixed to the high-strength prestressed anchor rod. A conical fastener at the tail end of the stress anchor rod; the middle section of the high-strength prestressed anchor rod is wrapped with a decoupling structure, and the decoupling structure is formed by wrapping a geomembrane around the middle section of the high-strength prestressed anchor rod; the head end of the high-strength prestressed anchor rod is sequentially provided with a cotton yarn filling section formed by cotton yarn surrounding the high-strength prestressed anchor rod, a tray and a fastener located outside the sleeve, wherein the tray can limit the part of the high-strength prestressed anchor rod extending out of the sleeve to the outer surface of the surrounding rock, and fix it by cooperating with the fastener; the grouting device can extend into the sleeve after passing through the tray.

[0007] According to some specific embodiments of the present invention, a self-aligning ball pad is further provided between the tray and the fastener, and the grouting device can extend into the sleeve after passing through the self-aligning ball pad and the tray.

[0008] According to some specific embodiments of the present invention, the tail end of the high-strength prestressed anchor rod is fixed to the reverse anti-slip device through a threaded connection.

[0009] According to some specific embodiments of the present invention, the high-strength prestressed anchor rod can withstand a preload greater than 100 kN.

[0010] According to some specific embodiments of the present invention, the sleeve is made of a steel pipe.

[0011] According to some specific embodiments of the present invention, the grouting device includes a grouting conduit for slurry transportation, which is inserted into the sleeve side by side with the high-strength prestressed anchor rod, and a valve arranged at the head end of the grouting conduit for regulating the slurry flow rate; the tail end of the grouting conduit is provided with a plurality of grouting holes for discharging the slurry into the sleeve.

[0012] According to some specific embodiments of the present invention, the total length of the grouting conduit is 20 to 30 cm greater than the total length of the high-strength prestressed anchor rod, and the tail end thereof is located before the resin anchor filling section.

[0013] The present invention further discloses a method for actively controlling large deformation of deep thin-layered surrounding rock using the above-mentioned active control device for large deformation of deep thin-layered surrounding rock, which comprises:

[0014] Step 1: After the rock mass is excavated, drilling is performed in the tunnel surrounding rock close to the tunnel face;

[0015] Step 2, installing the reverse anti-skid device at the tail end of the high-strength prestressed anchor rod, and sequentially installing the resin anchor, the decoupling structure, the sleeve and the cotton yarn, and then inserting the sleeve into the construction drill hole;

[0016] Step 3: After the resin anchoring agent solidifies and has a certain strength, the tray, the fastener and the grouting device are sequentially installed at the head end of the high-strength prestressed anchor rod;

[0017] Step 4: After completing the installation of step 3, applying a preload force of 100 to 200 kN to the high-strength prestressed anchor rod;

[0018] Step 5: After the surrounding rock stress adjustment is completed, grouting is performed into the sleeve through the grouting device, and the slurry enters the surrounding rock from the holes of the sleeve to achieve grouting reinforcement of the surrounding rock.

[0019] The present invention has the following beneficial effects:

[0020] (1) The control device of the present invention adopts a method of high-strength anchor rod prestressing combined with a resin anchoring agent, which can apply high prestress in a short time after the anchor rod is installed, quickly exert the anchoring effect, enhance the timeliness of anchor rod support, reduce the cracks caused by strong unloading of rock excavation under high ground stress conditions, and restore the true three-dimensional stress state of the surrounding rock.

[0021] (2) The control device of the present invention can perform delayed grouting when the surrounding rock is partially damaged and fractured due to stress adjustment in the later stage. After the anchor rod construction, the surrounding rock is further reinforced, the cracks in the surrounding rock are sealed, and the integrity of the surrounding rock is reshaped, thereby improving the strength of the surrounding rock.

[0022] (3) The control device of the present invention is provided with a decoupling structure, which can separate the anchor rod body from the grouting anchor body through the Poisson effect after the surrounding rock undergoes a large deformation, thereby preventing the anchor rod from being broken due to excessive local deformation.

[0023] (4) The control device of the present invention is provided with a sleeve, which can reduce the concentration of shear stress on the anchor rod when the surrounding rock slips along the bedding, thereby reducing the probability of the anchor rod being sheared off.

[0024] (5) The control method or device of the present invention is simple and reasonable, which reduces the cost of subsequent grouting and drilling, and can achieve dual use of one hole, with significant economic benefits.

[0025] (6) The control method of the present invention attaches importance to the timeliness of large deformation control of thin-layered surrounding rock in high-stress tunnels. The support measures used can immediately play an active support role after rock excavation to restore the true three-dimensional stress conditions of the surrounding rock and increase the self-bearing capacity of the surrounding rock as much as possible. In the later stage of surrounding rock stress adjustment, the anchor rods used can adapt to the deformation of the rock mass so that it will not be pulled or sheared off, and the surrounding rock damaged and fractured due to stress adjustment can be reinforced by delayed grouting. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the structure in the application of high-strength prestressed delayed grouting anchor rod in an embodiment of the present invention.

[0027] Figure 2 It is a schematic diagram of the decoupling structure arrangement in an embodiment of the present invention.

[0028] In the figure: 1-high-strength prestressed anchor rod, 2-resin anchor, 3-decoupling structure, 4-sleeve, 5-cotton yarn, 6-grouting catheter, 7-valve, 8-reverse anti-skid device, 9-tray, 10-self-aligning ball pad, 11-nut, 12-hole, 13-grouting hole. DETAILED DESCRIPTION

[0029] The present invention is described in detail below in conjunction with the embodiments and drawings, but it should be understood that the embodiments and drawings are only used to exemplify the present invention and do not constitute any limitation on the protection scope of the present invention. All reasonable changes and combinations within the scope of the inventive concept of the present invention fall within the protection scope of the present invention.

[0030] Step 1: After the rock mass is excavated, drilling is carried out in the tunnel surrounding rock close to the tunnel face;

[0031] Step 2: Install high-strength prestressed anchor components;

[0032] Step 3: Apply pre-tightening force to the anchor rod after the resin anchoring agent has a certain strength;

[0033] Step 4: After the stress adjustment is completed, carry out delayed grouting on the surrounding rock.

[0034] Furthermore, the high-strength prestressed anchor rod component comprises a high-strength prestressed anchor rod (1), a resin anchoring agent (2), a decoupling structure (3), a sleeve (4), cotton yarn (5), a delayed grouting device, a reverse anti-skid device (8), a tray (9), a self-aligning ball pad (10), and a nut (11); threads are processed at both ends of the high-strength prestressed anchor rod, and the specifications of the anchor rod match the reverse anti-skid device, the nut, the self-aligning ball pad and the tray; the nut, the self-aligning ball pad and the tray are installed at the head end of the anchor rod, and the reverse anti-skid device is installed at the tail end, and the decoupling structure is wrapped around the middle of the rod body; the anchor rod is inserted into the sleeve, and the delayed grouting device is placed side by side with the anchor rod in the drilled hole.

[0035] Furthermore, the pre-tightening force of the high-strength prestressed anchor rod is greater than 100 kN.

[0036] Furthermore, the decoupling structure is made of a woodworking soft film with strong elasticity and is evenly wound around the anchor rod body.

[0037] Furthermore, the sleeve is cut from a steel pipe, and holes (12) are opened on both sides of the sleeve.

[0038] Furthermore, the delayed grouting device comprises a grouting conduit (6) and a valve (7), wherein the valve is installed at the head end of the grouting conduit, 3 to 5 grouting holes (13) are drilled at the tail end of the grouting conduit, and the length of the grouting conduit is 20 to 30 cm greater than the length of the anchor rod.

[0039] Furthermore, the tray is drilled with a hole, the diameter of which is larger than the diameter of the grouting conduit.

[0040] Example 1

[0041] The large deformation active control device used is attached Figure 1 , 2 The high-strength prestressed delayed grouting anchor bolt shown in the figure comprises: a sleeve 4 with holes 12 on both sides, a high-strength prestressed anchor bolt 1 inserted in the sleeve and extending outside the sleeve 4, and a grouting device arranged side by side with the anchor bolt 1 and capable of grouting operation; a reverse anti-skid device 8 is provided at the tail end of the high-strength prestressed anchor bolt 1 extending into the deep thin layered surrounding rock through the construction hole, and a resin anchor filling section 2 formed by the applied resin anchoring agent and located at the front end of the reverse anti-skid device 8 between the high-strength prestressed anchor bolt 1 and the sleeve 4, wherein the reverse anti-skid device 8 is a conical tight fitting device that can be fixed to the tail end of the high-strength prestressed anchor bolt 1 Firmware, such as a conical nut; the middle section of the high-strength prestressed anchor rod 1 is wrapped with a decoupling structure 3, and the decoupling structure 3 is formed by a geomembrane with strong elasticity wrapped around the middle section of the high-strength prestressed anchor rod 1; the head end of the high-strength prestressed anchor rod 1 is sequentially provided with a cotton yarn filling section 5 formed by cotton yarn surrounding the anchor rod 1 and a tray 9, a self-aligning ball pad 10 and a nut 11 outside the sleeve, wherein the tray 9 can limit the part of the high-strength prestressed anchor rod 1 extending out of the sleeve 4 to the outer surface of the surrounding rock, and fix it by the cooperation of the self-aligning ball pad 10 and the nut 11, and the grouting device can pass through the self-aligning ball pad 10 and the tray 9 and then extend into the sleeve 4.

[0042] Preferably, the tail end of the high-strength prestressed anchor rod 1 is fixed to the reverse anti-skid device 8 by threaded connection.

[0043] Example 2

[0044] In the high-strength prestressed delayed grouting anchor rod of Example 1, the high-strength prestressed anchor rod 1 used can withstand a preload greater than 100 kN, and the sleeve used is made of a steel pipe.

[0045] Example 3

[0046] In the high-strength prestressed delayed grouting anchor rod of Example 1, the grouting device includes a grouting conduit 6 for slurry transportation inserted into the sleeve side by side with the high-strength prestressed anchor rod 1, a valve 7 is arranged at the head end of the grouting conduit 6 for regulating the grouting flow rate, and 3 to 5 grouting holes 13 are arranged at the tail end of the grouting conduit 6 for discharging the slurry in the grouting conduit 6 into the sleeve 4.

[0047] Preferably, the total length of the grouting conduit 6 is 20 to 30 cm greater than the total length of the high-strength prestressed anchor rod 1 , and its tail end is located before the resin anchor filling section 2 .

[0048] Preferably, the tray 9 is drilled with a hole, the diameter of which is larger than the diameter of the grouting conduit 6 , and the grouting conduit 6 extends into the sleeve 4 through the drilled hole.

[0049] Example 4

[0050] Using any one of the high-strength prestressed delayed grouting anchors in Examples 1-3 to actively control large deformation of deep thin-layered surrounding rock comprises the following steps:

[0051] Step 1: After the rock mass is excavated, drill holes in the tunnel surrounding rock close to the tunnel face;

[0052] Step 2: Install the reverse anti-skid device 8 at the tail end of the high-strength prestressed anchor rod 1, and install the resin anchor, the decoupling structure 3, the sleeve 4 and the cotton yarn in sequence, and then insert it into the drill hole;

[0053] Step 3: After the resin anchoring agent solidifies and has a certain strength, a tray, a self-aligning ball pad, a nut and a grouting device are sequentially installed at the head end of the high-strength prestressed anchor rod 1;

[0054] Step 4: After the installation of the high-strength prestressed delayed grouting anchor rod is completed, a preload force of 100 to 200 kN is applied to the high-strength prestressed anchor rod 1;

[0055] Step 5: After the surrounding rock stress adjustment is completed, grouting is performed into the sleeve 4 through the grouting device, and the slurry enters the surrounding rock from the hole 12 of the sleeve 4 to achieve grouting reinforcement of the surrounding rock.

[0056] The above embodiments are only preferred implementations of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. An active control device for large deformation of deep thin-layered surrounding rock, characterized in that: It includes: A sleeve with holes on both sides, a high-strength prestressed anchor rod inserted in the sleeve and extending outside the sleeve, and a grouting device that is parallel to the high-strength prestressed anchor rod and can perform grouting operations; the tail end of the high-strength prestressed anchor rod extending into the deep thin-layered surrounding rock through the construction hole is provided with a reverse anti-skid device and a resin anchor filling section formed by an applied resin anchor agent located at the front end of the reverse anti-skid device and between the high-strength prestressed anchor rod and the sleeve, wherein the reverse anti-skid device is a conical fastener that can be fixed to the tail end of the high-strength prestressed anchor rod; the middle section of the high-strength prestressed anchor rod is wrapped with a decoupling structure, and the decoupling structure is formed by geomembrane wrapped around the middle section of the high-strength prestressed anchor rod; the head end of the high-strength prestressed anchor rod is sequentially provided with a cotton yarn filling section formed by cotton yarn surrounding the high-strength prestressed anchor rod. A filling section and a tray and fasteners located outside the sleeve, wherein the tray can limit the part of the high-strength prestressed anchor rod extending out of the sleeve to the outer surface of the surrounding rock and fix it by the cooperation of the fasteners; the grouting device can extend into the sleeve after passing through the tray; the tail end of the high-strength prestressed anchor rod is fixed to the reverse anti-skid device by threaded connection; the grouting device includes a grouting conduit for slurry transportation inserted into the sleeve side by side with the high-strength prestressed anchor rod, and a valve arranged at the head end of the grouting conduit for regulating the slurry flow rate; the tail end of the grouting conduit is provided with a plurality of grouting holes for discharging slurry into the sleeve; the total length of the grouting conduit is 20~30cm greater than the total length of the high-strength prestressed anchor rod, and its tail end is located before the resin anchor filling section.

2. The deep thin-layered surrounding rock large deformation active control device according to claim 1 is characterized in that: A self-aligning ball pad is also provided between the tray and the fastener, and the grouting device can extend into the sleeve after passing through the self-aligning ball pad and the tray.

3. The device for actively controlling large deformation of deep thin-layered surrounding rock according to claim 1, characterized in that: The high-strength prestressed anchor rod can withstand a preload greater than 100 kN.

4. The device for actively controlling large deformation of deep thin-layered surrounding rock according to claim 1, characterized in that: The sleeve is made of a steel pipe.

5. A method for actively controlling large deformation of deep thin-layered surrounding rock using the deep thin-layered surrounding rock large deformation active control device according to any one of claims 1 to 4, comprising: Step 1: After the rock mass is excavated, drilling is performed in the tunnel surrounding rock close to the tunnel face; Step 2, installing the reverse anti-skid device at the tail end of the high-strength prestressed anchor rod, and sequentially installing the resin anchoring agent, the decoupling structure, the sleeve and the cotton yarn, and then inserting the sleeve into the construction drill hole; Step 3: After the resin anchoring agent solidifies and has a certain strength, the tray, the fastener and the grouting device are sequentially installed at the head end of the high-strength prestressed anchor rod; Step 4: After completing the installation of step 3, apply a preload force of 100-200 kN to the high-strength prestressed anchor rod; Step 5: After the surrounding rock stress adjustment is completed, grouting is performed into the sleeve through the grouting device, and the slurry enters the surrounding rock from the holes of the sleeve to achieve grouting reinforcement of the surrounding rock.

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