In-stratum stepped-heaped-weir-type safe grouting construction process for blocking large water gushing from sidewall of deep foundation pit

Abstract

The invention discloses an in-stratum stepped-heaped-weir-type safe grouting construction process for blocking large water gushing from a sidewall of a deep foundation pit. The safe grouting construction process comprises the following steps: the amounts of gushed water and silt from the sidewall at the deep part of the foundation pit are observed and calculated; a water drain pipe is arranged ina water gushing point to drain water; backpressure bodies are arranged around the water gushing point to form backpressure on the sidewall, of the foundation pit, around the water gushing point; holesare drilled in the surface of the sidewall where the water gushing point is positioned, the holes are divided into at least two rows, the depths of the first row of holes and the second row of holesare arranged in a vertically-stepped form, the first row of holes is near a supporting protective body of the sidewall, and the depths of the drilled holes decrease sequentially from inward to outward; and grouting is performed for blocking. Vertical drilling is carried out quickly in the surface on the outer side of the sidewall, where the water gushing point in the the deep part of the foundation pit is positioned; aggregate and anti-dispersion high-early-strength rapid-hardening grout are injected into a water guide channel or a formed cavity through the drilled holes to rapidly form a water-blocking curtain in a stratum where water gushes out, so as to block an underground water gushing channel and achieve the purposes of quickly controlling water gushing and by grouting, reinforcing the stratum damaged by water gushing.

Description

technical field [0001] The invention belongs to the field of grouting plugging of relatively large water gushing deep in the side walls of deep foundation pits such as urban subway tunnels and buildings, and in particular relates to a step stacking weir type safety grouting in strata for sealing large water gushing in the side walls of deep foundation pits construction process. Background technique [0002] When constructing urban subway tunnel stations and excavating deep foundation pits for high-rise buildings, it is often encountered that the water volume in the deep side wall of the foundation pit is not less than 10m 3 / h of the larger water gushing phenomenon. After the flooding, it brought a great security threat to the project. After analysis, the sources of water gushing in the deep part of the deep foundation pit are mainly underground diving, lateral recharge of surface rivers, or serious leakage of underground pipelines (sewage, rainwater, etc.). Water gushing...

AI Technical Summary

Problems solved by technology

In this case, the grouting method using side wall bolts is difficult to meet the requirements of continuous large-scale grouting due to the small amount of grouting, and the grouting depth of the bolts is shallow, which is top water grouting opposite to the direction of water flow. The diffusion range of the slurry is small, most of the injected slurry is washed out by the water flow, the water blocking effect is poor, and the construction period is long. It is possible that serious collapse and subsidence accidents will occur before the treatment effect is achieved.

Moreover, construction workers must be close to the side wall of the gushing water, which poses a high risk to personal safety.

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