硬岩地下连续墙潜孔锤跟管咬合引孔成槽施工技术

Construction Technology of Diaphragm Wall by Forming Interlocking Bored Holes with the Combination of DTH Hammer and Casing Pipe in Deep and Hard Rock

在地下连续墙成槽施工遇到深厚岩层时,旋挖取芯或冲击引孔时存在钻进速度慢、二序孔垂直度控制难,后期方锤冲击修孔难度大、施工效率低,综合成本高等问题。为此,采用大直径潜孔锤超设计桩径、全套管跟管、分序咬合式小间距引孔,引孔后采用带截齿的抓斗清槽,不需用方锤修孔,达到了成槽速度快、成槽质量好、安全可靠、综合成本低的效果。

When grooving for diaphragm wall using rotary drilling rig or hole puncher in deep and hard rock,there exists some problems such as slow drilling speed,difficulty in controlling the perpendicularity of secondary hole,difficulty in cleaning groove with square hammer in later stage,low construction efficiency and high comprehensive cost.To address these problems,this paper suggests a series of new technologies using DTH hammer with large drilling diameter to form thicker trench which exceeds groove’s designed thickness,to place full casing simultaneously while drilling secondary piles,to form small-spacing interlocking bored holes in sequence.The grab with pick teeth instead of square hammer is used to clean the hole after the hole leading.The construction method has achieved the effects of fast trenching speed,good quality,safety and reliability,and low comprehensive cost of constructing underground diaphragm wall.