CN-116838391-B - Connecting device for improving installation pretightening force of resin anchor rod and construction method

CN116838391BCN 116838391 BCN116838391 BCN 116838391BCN-116838391-B

Abstract

The invention discloses a connecting device for improving the installation pretightening force of a resin anchor rod and a construction method, and the connecting device comprises an outer cylinder and an inner cylinder, wherein the outer cylinder and the inner cylinder are arranged on the same circular mandrel line, a piston is arranged between the upper part of hydraulic oil in a cavity of the inner cylinder and the limiting disc, and the combined action of an overflow valve, a liquid return valve and an injection and discharge valve arranged on the outer wall of the inner cylinder can realize the integrated operation of stirring and installing the resin anchor rod. The hydraulic oil in the device forms internal circulation to avoid loss, and the oil pressure threshold value of the device is adjustable, so that the device can be matched with jumbolters with different thrusts and torques and resin anchors with different specifications, and has wide application range, convenient operation and wide application prospect.

Inventors

WU HAO
WEI LIJUN
ZHOU FAN
LI QIANG
WANG ZONGYONG
WANG WANLU
WANG MENGLAI
LI SHUJIAN
ZHANG BIN
LIU YINGHUI
MA DAN
ZHANG JIXIONG

Assignees

云南磷化集团有限公司
中国矿业大学

Dates

Publication Date: 20260508
Application Date: 20230802

Claims (8)

1. The connecting device for improving the resin anchor rod installation pretightening force is characterized by comprising an outer cylinder and an inner cylinder, wherein the outer cylinder and the inner cylinder are arranged on the same round mandrel line, the outer bottom of the inner cylinder is welded and fixed with the inner bottom of the outer cylinder through a bottom cylinder, the top of the inner cylinder and the top of the outer cylinder are connected into a whole through forging, so that the inner cylinder and the outer cylinder form a closed interlayer cavity, a connecting rod is arranged at the center of the outer surface of the bottom of the outer cylinder and is connected with an anchor rod drilling machine, a multistage clamping groove for fixing a resin anchor rod nut is arranged at the top of the inner cylinder, a limit disc is arranged between the multistage clamping groove and the inner cylinder cavity of the inner cylinder, hydraulic oil is injected into the interlayer cavity, a piston is arranged between the upper part of the hydraulic oil in the inner cylinder cavity and the limit disc, and the outer wall bottom of the inner cylinder is respectively provided with an overflow valve and a liquid return valve; the connecting device for improving the installation pretightening force of the resin anchor rod is used for a construction method of the resin anchor rod and comprises the following steps of: drilling anchor rod drilling holes matched with an anchor rod body according to a designed hole distribution position, and cleaning holes in time by adopting a pneumatic tool after drilling; (S2) opening a liquid return valve, determining whether hydraulic oil needs to be injected into the connecting device or not by checking whether the piston in the inner cylinder cavity is at an initial position, ensuring that the piston is in contact with the limiting disc, and closing the liquid return valve; (S3) determining an oil pressure threshold value of the overflow valve according to the pretightening force of the resin anchor bolt support design, wherein the oil pressure threshold value is calculated according to the following formula: ; Wherein p 0 is the oil pressure threshold of the overflow valve, F 0 is the design pretightening force of the anchor rod, and S represents the cross section area of the anchor rod body; (S4) preparing an jumbolter and installing a connecting device, then manually plugging 1-3 rolls of resin anchoring agent into a drilling hole, then assembling a rod body, a tray, a gasket and a nut into a whole and inserting the rod body, wherein the head of the rod body props against the anchoring agent, and the nut on the tail of the rod body is connected with the connecting device through a multistage clamping groove; (S5) opening the jumbolter, firstly lifting the jumbolter with a thrust force smaller than F 0 , slowly pushing the anchor rod to the bottom of a drilling hole, carrying out rotary stirring of the anchoring agent, stopping rotation after the nut cannot be screwed in by the movement of the piston and then drives the rod body to rotate, and standing for 30-60S to wait for the anchoring agent to solidify after stirring for 5-10S; (S6) after the stirring process is finished, increasing the thrust of the jumbolter to more than F 0 to continuously rotate the nut, releasing hydraulic oil in the inner cylinder cavity into the interlayer cavity through the overflow valve to enable the piston to generate damping movement, providing a stroke for screwing the nut, and continuously fastening the nut until the nut cannot be further screwed by increasing the thrust and the rotating speed of the jumbolter; And (S7) dismantling the machine tool, opening a liquid return valve of the connecting device, automatically returning hydraulic oil in the interlayer cavity to the inner cylinder cavity to realize oil pressure balance, automatically resetting the piston to an initial position, and completing installation.
2. The connecting device for improving the installation pretightening force of the resin anchor rod according to claim 1, wherein the inner diameter of the outer cylinder is 60-90 mm, the depth of the outer cylinder is 20-30 cm, the outer cylinder is made of steel, the wall thickness of the outer cylinder is 5-10mm, and an injection and discharge valve with the functions of injecting hydraulic oil into an interlayer cavity and releasing the hydraulic oil is arranged on the outer wall of the bottom of the outer cylinder.
3. The connecting device for improving the installation pretightening force of the resin anchor rod according to claim 1, wherein the inner diameter of the inner cylinder cavity is 24-26 mm, the inner cylinder is made of steel, the wall thickness of the inner cylinder is 22-37 mm, all levels of clamping grooves of the multistage clamping groove are matched and fixed with hexagonal nuts of different types, and the rotary buttons of the overflow valve and the liquid return valve are led out and installed on the outer wall of the outer cylinder respectively.
4. The connecting device for improving the installation pretightening force of the resin anchor rod according to claim 1, wherein the bottom column is made of steel, the diameter of the bottom column is smaller than the inner diameter of the inner cylinder, and the height of the bottom column is 3-5 cm.
5. The connecting device for improving the installation pretightening force of the resin anchor rod according to claim 1, wherein the diameter of the piston is equal to that of the cavity of the inner cylinder, the height of the piston is 10-20 mm, and the circumference of the piston is provided with an O-shaped sealing ring in a circumferential mode.
6. The connecting device for improving the installation pretightening force of the resin anchor rod according to claim 1, wherein the limiting disc is located at the bottom of the multistage clamping groove of the inner cylinder and fixedly connected with the wall of the inner cylinder through an embedded screw, the thickness of the limiting disc is 3-5 mm, and a circular hole with the diameter of 23-25 mm is formed in the center of the limiting disc.
7. The connecting device for improving the installation pretightening force of the resin anchor rod according to claim 1, wherein the number of the clamping groove stages of the multistage clamping grooves is 2-4, each stage of clamping groove is a hexagonal groove, and the depth of each stage of clamping groove is 5-10 mm.
8. A connection device for increasing the installation preload of a resin anchor as set forth in claim 1, wherein: the connecting rod is a hexagonal drill rod, the length of the connecting rod is 30-50 cm, the diameter of the connecting rod is 20-25 mm, one end of the connecting rod is welded at the center of the bottom of the outer cylinder, and the other end of the connecting rod is connected with a drilling anchor rod machine bayonet.

Description

Connecting device for improving installation pretightening force of resin anchor rod and construction method Technical Field The invention relates to the technical field of mine support, in particular to a connecting device for improving the installation pretightening force of a resin anchor rod and a construction method. Background Underground mining is the process of excavating a series of roadway projects in an underground rock mass to access the mass to extract and transport the ore to the surface. After the well engineering is excavated, the stress balance state of the original rock is destroyed, and stress field redistribution in surrounding rock is realized to realize stress concentration and unloading. The secondary stress field is an important force source for rock deformation damage and rock catastrophe, and how to keep the well clear and the stability of surrounding rock is the key of safe and efficient operation. When the excavated roadway reaches a certain exposure space, surrounding rocks must be supported in time to prevent disaster accidents such as roof falling, side walls and the like. Along with the continuous enrichment of geotechnical theory and engineering experience, the support mode is developed from the original wood support, arch support and section steel support to the anchor bolt support and the composite support, and the support technology system is increasingly perfect and mature. The anchor bolt support technology has the advantages of low cost, simple process, convenient operation, good reinforcement effect, high support efficiency and the like, and is widely applied to rock engineering, particularly mining fields. The resin anchor bolt support is a technology for reinforcing a rock-soil body by using a resin anchoring agent matched with an anchor bolt of various material (screw steel, round steel, glass fiber reinforced plastic and the like) rod bodies and surrounding rock through a bonding anchoring effect (full length, lengthening or end head anchoring), and consists of the resin anchoring agent, an anchor bolt body, a tray, a gasket and a nut, wherein the resin anchor bolt can rapidly and effectively control the deformation of the surrounding rock due to short curing time. At present, an end socket or lengthened anchoring mode is generally adopted in mine roadway engineering to support surrounding rock, and the working flow comprises the steps of firstly constructing anchor rod drilling holes with a certain depth and a certain aperture in roadway surrounding rock by adopting an anchor rod machine tool, then manually plugging 1-3 rolls of resin anchoring agent matched with the aperture, then installing an anchor rod body with a certain length and a certain diameter by means of the anchor rod machine tool, pushing the anchoring agent into the bottom of the drilling hole, then carrying out rotary stirring, installing a tray, a gasket and a nut after the anchoring agent is solidified for a certain time, and finally tightening the nut by means of a torque wrench to apply pretightening force. In engineering, in order to simplify the process, a downhole worker usually performs rotary stirring by pushing an anchor rod assembled with a tray, a washer and a nut into an anchor hole to install the anchor rod by means of a pneumatic rock drill or an anchor rod drilling machine with an anchor rod installation connector until the tray contacts a surrounding rock surface. Obviously, the pretightening moment of the anchor rod in the installation mode is difficult to reach more than 100 N.m, because the screw thread length at the end part of the anchor rod is insufficient, the nut is quickly rotated to the screw thread root part under the rotation action, so that the anchoring agent cannot be rotationally fastened after solidification, the installation of the anchor rod is not in the order of push-first and rotation-second, the machine tool is removed when the anchor rod is pushed to the surrounding rock surface and the anchor agent is not completely solidified, the anchor rod can be removed from the anchor rod to outwards move under the action of the dead weight of the material and the extrusion rebound of the tray and the metal net, the pretightening force is reduced or even lost, the rated torque of construction machines such as a pneumatic rock drill, a common anchor rod drilling machine and the like is insufficient, the washer is not installed, or the friction coefficient of the screw thread of the nut is large, the diameter of the anchor rod is small, the friction coefficient between the nut and the washer is large, and the conversion coefficient of the pretightening force and pretightening moment is small. In recent years, in the field of coal mines, an anchor rod torque multiplier for increasing torque by reducing rotation speed based on a speed reducer principle and a torque nut for realizing stirring and mounting integration are applied to increase the anchor rod torque f