Pile forming method for jet grouting pile in flowing water sand layer

Abstract

The invention discloses a pile forming method for a jet grouting pile in a flowing water sand layer. The pile forming method comprises the steps that S1, a geological drilling rig is adopted for drilling; S2, clay powder is adopted and mixed with efficient high-foaming bentonite, and first-time jet grouting jetting is conducted in a drilled hole; and S3, cement paste and water glass are adopted for conducting second-time jet grouting jetting in the drilled hole at the same time, the pressure of the second-time jet grouting jetting is smaller than that of the first-time jet grouting jetting, and the lifting speed of the second-time jet grouting jetting is larger than that of the first-time jet grouting jetting. According to the pile forming method, the second-time jet grouting jetting is adopted in the flowing water sand layer; the second-time jet grouting jetting is adopted in the same drilled hole, the clay powder and the bentonite paste of the first-time jet grouting jetting are used for stabilizing gaps between the sand layer and sand grains filling the sand layer firstly, and the sand layer is changed into a sand and soil mixture; and an efficient water reducing agent is added in the cement paste of the second-time jetting, the cement paste of the second-time jet grouting jetting can be prevented from being diluted or washed away or taken away by underground water before being solidified, the success rate of pile forming is increased, and the quality of the jet grouting pile is guaranteed.

Description

technical field [0001] The invention relates to a method for forming piles with rotary jetting, in particular to a method for forming piles with rotary jetting in dynamic water sand layers. Background technique [0002] In construction, transportation and water conservancy projects, it is necessary to build basements or excavate trenches to build foundations; at this time, foundation pit support and water-stop curtains are required. Cast-in-situ piles are usually used for the support piles of deep foundation pits, and the water-stop curtain is usually used as a water stop around the cast-in-place piles with Ф600 mixing piles, large-diameter stirring piles, and three-axis stirring piles, or additional support between the cast-in-place piles. Two single-pipe or double-pipe rotary spraying are used as water stop for rotary spraying piles between piles. After the application, the seepage and impermeability of the cement-soil piles stirred by the stirring piles or the rotary gro...

AI Technical Summary

Problems solved by technology

[0003] When water-stop curtains are used in areas near rivers, rivers and lakes, or in areas with complex hydrogeology such as coastal areas, when encountering deep and thick sand layers or pebble layers rich in water and under the pressure of groundwater, or the groundwater rises with the tide , When falling and flowing, the cement slurry added to the cement soil formed by the mixing pile or the rotary grouting pile will be washed and taken away by the passive water before it solidifies, resulting in the failure of the stirring or rotary grouting pile to form a pile and the failure of the water-stop curtain To stop the water and intercept the function of groundwater, and then lead to the leakage of foundation pit, resulting in serious quality accidents of the project

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