深圳花岗岩地区嵌岩桩入岩界面判断探讨

Determination of Rock-socketed Pile Interface in Granite Area of Shenzhen,China

由于受裂隙发育和不均匀风化的影响,导致中等(微)风化基岩面起伏大,软弱夹层和球状孤石普遍存在,嵌岩桩入岩界面的准确判定成为关键,而目前尚未有统一的判定标准和方法。以深圳市花岗岩地区地层特点为背景,依托某高层建筑嵌岩桩工程实例,从勘察与施工角度对嵌岩桩入岩界面判断进行工程经验总结。结合低应变法与现场载荷试验,对承载力要求较高的单桩承载力效果进行了评价。根据试验结果分析,受检桩桩身完整性类别为Ⅰ类,单桩竖向抗压承载力检测值皆达到载荷试验要求最大荷载,满足设计要求。

Affected by the development of fissures and uneven weathering,the surface of the medium-or micro-weathered bedrock has significant undulations,companying with weak interlayers and spherical boulders.The correct determination of the rocksocketed pile interface is the key,but there are no unified judgment standards and methods at present.Accordingly,with the background of the characteristics of granite strata in Shenzhen,relying on the engineering example of a high-rise building embedded rock pile,the engineering experience of the rock-socketed pile interface determination from the perspective of investigation and construction were summarized.Combining the low-strain integrity test and the field load test,the bearing capacity effect of a single pile with higher bearing capacity requirements was evaluated.According to the test results,the integrity of the pile body was evaluated as classⅠ.The measured values of vertical compressive bearing capacity of single pile meet the maximum load required by the load test and meet the design requirements.