大连临海超大深基坑旋喷桩止水帷幕施工技术

Technology of Rotary Jetting Pile Curtain Construction in Ultra Large Deep Foundation Pit in Dalian Coastal Area

摘要:

大连临海区域地貌为冲海积阶地，后经人工回填，地质水文条件复杂，既有天然沉积的土层和岩石，又有人工回填的透水性很强的杂填土。其地下水位受海水影响，下部为卵砾石及强风化基岩，基岩面起伏较大。地铁车站超大深基坑开挖采用桩基围护结构加止水帷幕，坑内深井井点方式降水。通过两次试桩及工艺参数优化，高压旋喷桩止水帷幕达到理想效果。

Abstract:

Because of the artificial backfilling, the geological and hydrological conditions are complicated in Dalian near sea region, which was alluvial marine sedimentation terrace. The natural deposit soil and rock exists with strong permeable backfilled miscellaneous soil-filling. Pile foundation pit enclosure structure, water-proof curtain and deep well point dewatering were adopted for ultra large deep foundation pit excavation. By 2 pile tests and process parameters optimization, it was proved high pressure jet grouting pile waterproof curtain achieved ideal effect.