Rotary excavating and drilling half-hole mud wet-method hole formation process of collapsible loess super-length large-diameter pile foundation

Abstract

The invention provides a rotary excavating and drilling half-hole mud wet-method hole formation process of a collapsible loess super-length large-diameter pile foundation and belongs to the technicalfield of pile foundation rotary excavating and drilling hole formation. The process comprises the following steps: confirming pile foundation rotary excavating and drilling half-hole mud wet-method hole formation conditions, flattening a field, burying protection barrels, making mud, drilling holes, cleaning the holes, manufacturing reinforcement cages, mounting the reinforcement cages, mounting guide tubes, and grouting concrete. According to the half-hole mud wet-method hole formation process provided by the invention, dry-method mud-free hole formation is implemented in an upper crack sinkhole development section, a rapid speed can be achieved, a hole wall can be extruded by a drilling hopper, and the hole wall stability can be improved; mud wall protection wet-method hole formation isimplemented in a lower part, hole collapse can be effectively prevented, and a hole formation speed can be ensured; a good mud wall protection effect can be achieved, remarkable effects in reducing hole collapse and the like can be achieved, and the security can be easily ensured; holes can be cleaned through bottom blowing and slag turnover and positive circulation of high pressure water, or bydoping mud or clean of a low density at the hole bottoms to directly dilute the mud, slag settled at the hole bottoms can be completely cleaned off, the possibility that the settled slag is mixed withthe mud in pile foundation concrete can be reduced, and the quality can be easily ensured.

Description

Technical field [0001] The invention belongs to the technical field of pile foundation rotary excavation and drilling, and specifically relates to a semi-hole mud wet hole forming process for collapsible loess ultra-long and large-diameter pile foundation rotary excavation and drilling. Background technique [0002] Since the beginning of the new century, as the people’s requirements for driving comfort have increased, the design longitudinal slopes of high-grade railways and highways have gradually decreased, and there have been more and more large-span and high-pier bridges. The bearing capacity of the foundation is required to be large. In particular, most of the geology in Shaanxi and Gansu in northern my country is collapsible loess. Due to the thicker soil layer of collapsible loess and low pile side friction resistance, various long pile foundations over 50m have emerged. The characteristics of a long pile foundation are the long pile foundation, large diameter, thick soi...

AI Technical Summary

Problems solved by technology

The characteristics of the long pile foundation are that the pile foundation is long, the hole diameter is large, the soil layer of the pile wall is thick, the self-stability is poor, the hole forming, the reinforcement cage installation, the concrete pouring time is long, it is easy to collapse, the mud sedimentation speed is fast, and the sedimentation volume is large, so the construction is difficult. How to quickly, safely, economically and environmentally friendly complete the construction of long pile foundations in collapsible loess areas has always been a problem that plagues construction