Special-grouting-based grouting system with adjustable moving cavity pressure and grouting method thereof

Abstract

A grouting system with an adjustable moving cavity pressure. The grouting system includes a master grouting pipe and a plurality of grouting valve pipes connected to the master grouting pipe, each grouting valve pipe is in an annular space within a borehole wall, the grouting valve pipe includes a grouting valve pipe body, and a spraying valve port is on the grouting valve pipe body. A grouting pipe, an air injection pipe and a movable piston are inside the grouting valve pipe body. The air injection pipe is connected with the movable piston to apply an air pressure into the movable piston, and the movable piston applied with the air pressure expands in volume to form a closed cavity between a lower part of the movable piston and the grouting valve pipe body, so that grouting is performed according to the position of the movable piston.

1 . A special-grouting-based grouting system with an adjustable moving cavity pressure, comprising a master grouting pipe and a plurality of grouting valve pipes connected to the master grouting pipe, wherein each grouting valve pipe is located in an annular space within a borehole wall;
 the grouting valve pipe comprises a grouting valve pipe body, and a spraying valve port is disposed on the grouting valve pipe body;   wherein a grouting pipe, a air injection pipe and a movable piston are disposed inside the grouting valve pipe body, an outer diameter of the movable piston is smaller than an inner diameter of the grouting valve pipe body, the air injection pipe is connected with the movable piston to apply an air pressure into the movable piston, and the movable piston applied with the air pressure expands in volume to form a closed cavity between a lower part of the movable piston and the grouting valve pipe body, so that grouting is performed for the grouting valve pipe body according to the position of the movable piston;   the grouting pipe penetrates through the movable piston to perform grouting into the grouting valve pipe body.   
     
     
         2 . The special-grouting-based grouting system with an adjustable moving cavity pressure according to  claim 1 , wherein a different grouting pressure in each grouting valve pipe is designed by adjusting a size of the air pressure applied into the movable piston through the air injection pipe. 
     
     
         3 . The special-grouting-based grouting system with an adjustable moving cavity pressure according to  claim 1 , wherein a plurality of spraying valve ports are disposed, and a valve port protection pad is fixedly connected at each spraying valve port to temporarily prevent a target object from blocking the spraying valve port during mounting. 
     
     
         4 . The special-grouting-based grouting system with an adjustable moving cavity pressure according to  claim 3 , wherein the valve port protection pad is fixed at the corresponding spraying valve port in a binding manner. 
     
     
         5 . The special-grouting-based grouting system with an adjustable moving cavity pressure according to  claim 1 , wherein the air injection pipe is connected with an air supply apparatus which injects air into the air injection pipe. 
     
     
         6 . A special-grouting-based grouting method with an adjustable moving cavity pressure using the special-grouting-based grouting system with an adjustable moving cavity pressure according to  claim 1 , comprising the following steps sequentially:
 at step S 1 , arranging each grouting valve pipe in an annular space within a borehole wall after drilling, and mounting the grouting pipe, the air injection pipe and the movable piston in the grouting valve pipe body while ensuring the connections of the device are made fully and reliably;   at step S 2 , injecting air into the air injection pipe to enable the movable piston connected with the air injection pipe to gradually expand so as to form a closed cavity between the lower part of the movable piston and the grouting valve pipe body;   at step S 3 , when different grouting pressures are needed in different grouting valve pipes according to a geological condition, adjusting the grouting pressures in different grouting valve pipes according to different amounts of air injected into the air injection pipes in different grouting valve pipes;   at step S 4 , when a different grouting pressure is needed in the same grouting valve pipe, forming a closed cavity with a different height between the lower part of the movable piston and the grouting valve pipe by injecting a different amount of air, so as to adjust the grouting pressure in the same grouting valve pipe; and   
       at step S 5 , repeating step S 3  or S 4  until the entire grouting process is completed.