摘要
为确保复合地层条件下水下挖孔灌注桩施工顺利,以猫铺2号大桥为背景,采取集水坑截水、无渗透排水等措施进行桩基施工。在河道上、下游远离桩基15m处分别开挖1个上口半径8m的集水坑,自然放坡,深度开挖至砂卵石层底;在河道上、下游远离施工区域挖掘1条宽2m、深1.5m的倒梯形水渠并铺设塑料薄膜,进、出水口设置在集水坑影响范围外;在集水坑位置搭设支架,安装倒链拴大流量潜水泵,将集水坑内的水泵至水渠内;采用间隔交错跳挖施工顺序施工水下挖孔灌注桩。在河滩砂卵石地层相同施工条件下,挖孔桩成孔和冲击成孔的工期、造价与环保效益的对比结果表明:对于单排4根桩,挖孔灌注桩的工期、造价分别为52d、103 832元,均小于冲击成孔的工期和造价且较为环保。
To ensure the smooth construction of the underwater dug piles under the conditions of compound stratum,the Maopu Bridge No.2 was cited as an example,the piles of the bridge were constructed by the measures of collecting water by the catch pits and dewatering with no seeping.At the places of 15 m far from the piles upstream and downstream in the river channel,a catch pit with its upper radius being 8 m and with natural slope was respectively excavated to the sand and pebble layer and at the place far from the construction area,an inverted trapezoidal water channel,2 m wide and 1.5 m deep,was also excavated and was laid with the plastic sheets.The water inlet and outlet were set beyond the influential range of the catch pit and at the catch pit,the scaffolding was set up and the high flow chain submersible pumps were installed.The water in the catch pits was pumped out to the water channel and the underwater dug piles were constructed by the construction sequences of alternative and interval excavation.The comparison of the construction time schedules,cost,and environment benefits of the dug holes with those of the percussively bored holes of the piles under the same construction conditions of sand and pebble layer in river shore indicate that for the 4 piles in a single row,the construction schedule and cost of the dug piles are respectively 52 d and RMB Yuan 103 832,which are all less than those of the percussively bored holes and are more environment-protective.
出处
《桥梁建设》
EI
CSCD
北大核心
2012年第A01期131-134,共4页
Bridge Construction
关键词
桥梁
人工挖孔灌注桩
复合地层
集水坑
无渗透排水
bridge
manually dug pile
compound stratum
catch pit
dewatering with no seeping
