Long-spiral replaceable and extruded borehole construction

Abstract

A construction method follows the steps as: select proper driving head, spiral auger and star-pattern drilling bit according to the depth of the stone layer and pile length; drilling at low speed to designed position; Upon reaching the stone layer, move out the drill; fill clay back to the hole till above the stone layer; install a clay pressing device to the helical lobe on the spiral auger; drill in again till designed position; move out the drill and put in reinforce cage and concrete.

Description

Technical field The invention relates to a construction method for forming a hole for slope protection piles in a deep foundation pit supporting project, in particular to a construction method for long spiral replacement and compaction drilling. Background technique With the continuous development of urban architecture, the shape of buildings is also constantly developing towards super-large, super-high, and super-deep. Due to the gradual deepening of the excavation depth of the foundation pit, the difficulty of supporting the foundation pit is also increasing. Especially in the western half of the Beijing area, a layer of sand and gravel is commonly found, which is characterized by large thickness, high density and grain size. The large diameter brings great difficulty to the hole formation of the long auger drill, so that many projects cannot use the long auger drill for hole formation, and have to use other hole formation methods. How to improve the hole forming process of th...

AI Technical Summary

Problems solved by technology

1. The content of pebbles in the sand and pebble layer is relatively high, and the drilling tool does not penetrate the footage;

2. When the particle size of the pebbles in the sand and pebble layer is large, the large-size pebbles cannot be brought up during the hole-forming process, which often causes drill holding and sticking;

3. When the sand and pebble layer is thick, because of poor self-support, the phenomenon of hole collapse after lifting the drill is serious;

4. When the sand and pebble layer contains a small amount of stagnant water or residual water, it is easy to form quicksand, and the hole collapse of the pile hole is serious, so it is very difficult to construct the hole for the slope protection pile

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