Positive pressure and negative pressure combined grouting method

Abstract

The invention relates to a positive pressure and negative pressure combined grouting method, belonging to a method for formation of a waterproof curtain and grouting and water plugging of cracking rocks in underground project construction. According to the method, three grouting shock tubes, two negative pressure grouting tubes and one positive pressure grouting tube are adopted, the two negative pressure grouting tubes are connected with a vacuum pump of 1 standard atmospheric pressure, and the one positive pressure grouting tube is connected with a slurry storage tank. Under effects of a pressure gradient formed by positive pressure and negative pressure, slurry flows with smaller resistance and at a higher speed along a cracking channel formed by a positive tube A, a negative tube B and a negative tube C, the tube A and the tube B are moved clockwise into an area adjacent to the tube C when the slurry is diffused to the centers of the negative tube B and the negative tube C, and the steps are repeated until a round closed waterproof curtain is formed. By adopting the method, slurry blockage in the traditional single-tube pressure grouting method can be avoided, the waterproof curtain can be formed easily, slurry can be saved, and significant technical advantages and economic values can be achieved, and the method is particularly suitable for sand layers, silt layers and cracking rocks with good water permeability.

Description

technical field [0001] The invention relates to a water-stopping method for forming a water-stop curtain and cracked rock mass grouting in underground engineering construction, in particular to a combined positive and negative pressure grouting method. Background technique [0002] Both the temporary support structure and the permanent support structure in underground engineering construction are faced with the intrusion of groundwater. Under the action of underground confined water for a long time, the anti-seepage performance of the support structure gradually deteriorates. The grouting can effectively improve the stratum conditions and improve the bearing capacity of the foundation while realizing the grouting water shutoff. The traditional grouting method generally adopts "positive pressure grouting", and the formation of the water-stop curtain requires the grout to spread and overlap between adjacent grouting pipes. However, adjacent grouting pipes cannot control the a...

AI Technical Summary

Problems solved by technology

The external load directly acts on the soil skeleton or particles, and the soil particles are "passively" rearranged. During the rearrangement of the particles, the fine particles are broken and filled, which is prone to blockage, thereby reducing the flow rate of the grout and increasing the grouting pressure.

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