杭州湾大桥含生物气层工程特性研究

为了了解浅层气对杭州湾大桥工程的影响及制定工程对策，采用工程物探、钻探、室内模拟试验相结合的方法进行研究，得出了浅层气对打入桩基础基本无影响、无控释放对地基土扰动明显、有控制释放可消除其不和影响的结论，提出了钻孔桩基础施工前应提前采取有控制放气、成孔时加长孔口护管、加大泥浆比重、保证孔内液面高度、驱散和防止引燃从孔内溢出的气体等对策。

On Engineering Property of Biogenetic Gas Layer in Hangzhou Bay Bridge

In order to understand the influence of shallow gas on Hangzhou Bay Bridge and determine the prevention countermeasures,the combined methods of engineering geophysics,drilling and laboratory experiment are employed.From the study,it is concluded that there is no influence of shallow gas on the driven pile foundation,the disturbance of soil is caused by non-controlling gas release obviously,and the adverse effects of gas can be eliminated by the controlled gas release.Moreover,the countermeasures such as gas release under control condition before the drilling pile foundation construction,lengthening steel tube,increasing mud specific gravity,ensuring the whole liquid heights,dispersing and preventing ignition of gas from the overflow whole during the bored drilling are presented.