嵌岩桩承载力不足原因分析及综合加固处理

CAUSE ANALYSIS OF INSUFFICIENT BEARING CAPACITY FOR SOCKETED PILE AND ITS REINFORCED MEASURES

在对某工程中基桩进行高应变动力检测抽检时,发现部分嵌岩桩承载力未达到设计要求,通过钻芯法验证发现:部分基桩桩端沉渣过厚,另有部分基桩桩端未达到进入中等风化岩层的设计要求。该嵌岩桩采用冲击成孔法施工,出现事故的主要原因是上部填土和松散粉土部位未做护筒且泥浆未按要求制配,导致塌孔发生。针对工程的实际状况,对工程基桩进行了全面抽芯检测,根据桩端有无沉渣和桩端持力层的实际情况制定不同的加固方案,取得了理想的加固效果。

By the high strain dynamic testing method testing,it was discovered that the bearing capacity of socketed piles did not meet the design requirements in a resident engineering. To analyze the core specimen drilled form the engineering pile,heavy sediments were found at pile ends,even the piles end didn＇t get into the bearing stratum.The socketed pile was bored by impact holing method and the main cause was hole collapse due to no pile casing appliment and substandard coating mud in filling layer and loose silt layer. All piles were tested by drilling core method and different reinforcing schemes were made according to the actual condition of pile ends and the ideal reinforcement effect was obtained.