Construction method for foundation pit wall body of complex stratum with soft upper part and hard lower part

Abstract

The invention belongs to the technical field of deep foundation pit construction, and particularly discloses a construction method for a foundation pit wall body of a complex stratum with soft upper part and hard lower part. The construction method comprises the steps that S1, survey lofting, equipment entering and equipment positioning are conducted; S2, a full-casing full-rotary drilling machine is adopted to vertically guide holes to the level of a hard rock stratum, then a down-the-hole hammer drilling machine is adopted to continue excavation to the groove bottom, guide holes are formed, and at least two guide holes are drilled along the center line of the foundation pit wall; S3, a guide wall groove is excavated along the side boundary of the foundation pit wall body, and concrete is symmetrically cast in place on the two sides of the guide wall groove to form guide walls; S4, in the slurry wall protection state, a trenching machine is adopted to excavate a soil body between the hole sites till the elevation of the hard rock stratum; and S5, in the slurry wall protection state, a slot milling machine is adopted to excavate the hard rock part of the soil body between the hole positions till the slot bottom, and the down-the-hole hammer drilling machine is adopted to assist in crushing the hard rock. According to the combined grooving construction method, the grooving quality is ensured, the construction assembly line is formed, the grooving work efficiency is improved, and the combined grooving construction method has very high application value.

Description

technical field [0001] The invention belongs to the technical field of deep foundation pit construction, and more specifically relates to a method for constructing a foundation pit wall in complex formations with upper softness and lower hardness. Background technique [0002] Nowadays, the demand for the use of underground space is increasing, and the excavation depth of foundation pits is getting deeper and deeper. As the foundation pit support structure, the underground diaphragm wall has high rigidity, high strength and good impermeability. With the advantages of low noise and low vibration, the application is becoming more and more widely, and it is widely used in construction projects such as subway stations and deep foundation pits of ultra-deep underground projects. At present, the special machines used for grooving in China include rotary cutting multi-head drills, guide plate grabs, etc. However, when troughing in complex strata, using a single mechanical device f...

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Problems solved by technology

[0003] Aiming at the defects of the prior art, the object of the present invention is to provide a construction method for the foundation pit wall in complex strata with upper softness and lower hardness, which adopts a full-sleeve full-rotary drilling machine, a down-the-hole hammer drilling machine, a groove forming machine and a groove milling unit to synthesize grooves The construction of the underground diaphragm wall aims to solve the problems of low construction efficiency, serious mechanical equipment wear and high construction cost due to the use of a single trough-forming equipment in the traditional trough-forming construction process

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