Rotary excavating and drilling method for polymer and bentonite mixed mud

Abstract

The invention discloses a rotary excavating and drilling method for polymer and bentonite mixed mud. The rotary excavating and drilling method includes the steps that firstly, polymer mud and bentonite mud are prepared in two tanks respectively, the funnel viscosity of the polymer mud is controlled in the range of 30-36 s, the specific gravity of the bentonite mud is controlled to be 1.05, and the pH value of the polymer mud and the pH value of the bentonite mud are controlled in the range of 8-10; secondly, a steel protection cylinder is buried in a conventional method; thirdly, the polymer mud is injected into a hole, and drilling begins to be conducted; fourthly, when leakage happens, the bentonite mud is injected into the hole, and drilling is conducted continuously; fifthly, drilling is stopped for 15-30 min when drilling is conducted to the position above the bottom elevation of the design hole by 50 cm to 100 cm, and then drilling is conducted to the bottom elevation of the design hole; sixthly, mixed mud processing is conducted. The rotary excavating and drilling method has the advantages that the drilling footage speed is high and the mud leakage is small, the comprehensive cost of construction can be obviously reduced, and the technical problems that leakage is large when polymer mud is adopted by a rotary excavating and drilling machine under the conditions of deep and thick sand layers and stratums without underground water and with sparse upper portions and very dense middle and lower portions, and the drilling footage speed is low when bentonite mud is adopted are solved effectively.

Description

technical field [0001] The invention relates to a rotary drilling method, in particular to a rotary drilling method using polymer and bentonite mixed mud wall protection, and belongs to the technical field of foundation construction. Background technique [0002] In the industrial construction projects in the desert fringe areas of Northwest China, the original landforms of the construction sites are mostly sand dunes of various sizes, and the strata are mainly Quaternary Holocene aeolian sandy soils. After the construction site is leveled, generally the upper sand layer is relatively loose, while the middle and lower sand layers are very dense. When carrying out the construction of rotary drilling bored piles in these construction sites, polymer mud or bentonite mud wall drilling technology can be used. Due to the dry climate and deep underground water in desert areas, the drilling speed is faster when drilling with polymer mud retaining wall, but the polymer mud seeps qui...

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Problems solved by technology

Due to the dry climate and deep underground water in desert areas, the drilling speed is faster when drilling with polymer mud retaining walls, but the polymer mud seeps quickly in the upper loose sand layer, and the single-hole mud consumption is large, resulting in high construction costs. When bentonite mud is used for construction, the mud leakage in the upper sand layer is significantly reduced, but the dense sand layer in the middle and lower parts forms "iron sand" in the drill hole, and the drill bit "skids" at the bottom of the hole during rotary drilling , each time the footage is only 5-15cm, the time for forming a single hole is very long, and the reduction in construction efficiency leads to a sharp increase in the comprehensive cost of construction

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