深厚碎石回填层旋挖成孔处理工艺研究  

Study on Rotary Excavating Bucket Drilling Completion Treatment Process in Deep and Thick Detritus Backfill Layer

作　　者：黄邦杰 Huang Bangjie(China Coal Changjiang Foundation Construction Corporation,Nanjing,Jiangsu 210046)

机构地区：[1]中煤长江基础建设有限公司,南京210046

出　　处：《中国煤炭地质》2022年第6期51-54,共4页Coal Geology of China

摘　　要：在国家电网恩施高压柔性直流换流站项目中,桩基础采用钢筋混凝土灌注桩。由于施工地层情况为全石灰岩碎石回填区域,为保证施工的质量、安全、进度,将原计划的冲击钻冲击成孔工艺改为旋挖钻机钻进成孔施工工艺。在旋挖试成孔现场施工试验中,对6根试桩分别进行测试和分析,结果显示:当孔深较大时,黏土护壁只能短时间内保证孔壁的稳定,施工钻头产生扰动造成孔的坍塌。建议对于深度较大的桩基孔,在出现坍塌时,应及时提钻灌注水泥砂浆,待水泥砂浆终凝后继续复打挖孔,如此往复循环,直到开挖至满足设计孔深要求及入岩深度的处理工艺。In the Enshi high-voltage flexible DC converter station project of State Grid,the reinforced concrete cast-in-place pile has been used in pile foundation.Owing to the construction target is all limestone detritus backfill layer,to ensure construction quality,safe and rate of progress have changed original planned percussion drilling completion treatment process into rotary excavating bucket drilling completion treatment process.During the rotary excavating bucket drilling completion treatment process site testing has carried out testing and analysis for 6 testing piles separately.The result has shown that when drilling depth is deeper,the clay wall cake can be only kept wall stability a short time,drilling bit caused turbulence will cause borehole collapse.When collapse happened,to deeper pile foundation holes,drilling tools should be lifted and grouted in cement-sand grout promptly.After the grout final set,drilling will be continued,in such cyclic reciprocating,until excavation can satisfy designed requirements and excavated depth into rock.

关 键 词：混凝土灌注桩 旋挖成孔 回填层 塌孔处理 

分 类 号：TU44[建筑科学—岩土工程]