砂土-微风化岩复合地层地下连续墙成槽技术

针对砂土-微风化岩复合地层地下连续墙施工中微风化岩成槽困难的问题,提出了对微风化岩石爆破预处理的方法。采用微差毫秒爆破方法对微风化岩中地下连续墙边界及内部依次进行爆破,确保开挖面平整并控制冲击波能量对周围区域的影响。针对岩面以上为砂层地质易塌孔的问题,采用在岩面以上加钢套管的方式钻孔、成孔后下PVC管进行保护。与传统挖槽方法相比,深孔爆破法不仅破岩效果好,且大大缩短了工期。

TRENCHING TECHNOLOGY OF UNDERGROUND DIAPHRAGM WALL IN A SLIGHTLY-WEATHERED ROCK COVERED BY SAND

It is very lowly efficient to use the traditional trenching machine in rock to solve the typical problem encountered by trenching of underground diaphragm wall in a slightly-weathered rock covered by sand.To overcome this problem,blasting was proposed as the pretreatment of slightly-weathered rock.The millisecond short delay blasting was adopted between the boundary of diaphragm wall and the rock inside so that the flatness of the excavation surface could be guaranteed,and the effect of the shock wave energy on the surroundings could be alleviated.For the rock surface above the sand layer,it was easy to collapse during drilling holes.A steel casing pipe was installed during drilling,and a PVC pipe was installed after drilling to protect the hole.Compared with the traditional method,the deep-hole blasting method not only has a good rock breaking effect,but also greatly shortens the construction period.