某大吨位工程桩静载不合格原因分析及处理办法

Cause analysis and disposal method of static load failure of a large tonnage engineering pile

某大吨位冲孔灌注工程桩,单桩竖向抗压静载试验检测单桩竖向抗压极限承载力达不到委托最大试验荷载的第4级,比对附近桩基静载数据、综合地质资料、施工记录、持力层验孔留样进行分析,选择用钻芯法检查桩身完整性、桩底沉渣和桩端持力层性状,另外在该不合格桩附近用钻机进行足够深度的地勘,该桩静载不合格原因为地质复杂存在夹层,勘察不充分未能探明夹层性状,冲孔过程中只穿透了夹层,持力层不满足设计要求,提出了处理方法,该工程事故造成大量人力、物力、工期的再投入,经济损失严重,因此为避免此类问题再度发生,提出了相应的对策,对类似工程问题具有一定的参考价值和意义。

The single pile vertical ultimate bearing capacity of a large tonnage bored pile did not approach the fourth level of test loads in static load test. Through analysis of comparing the static data of nearby pile, combining geologic data, construction records and analysis of the bearing layer inspection hole, core drilling method inspection was selected to inspect the pile integrity, pile bottom sediment and pile end bearing layer characteristics. The enough depth geological exploration was made by drilling near this unqualified pile. It was founded that the failure of pile static load is due to the existence of complex geological dissection, inadequate investigation to clarify sandwich traits, punching process only penetrated through dissection, the bearing layer does not meet the design requirements. So treatment method was put forward. The engineering accident caused waste of large number of manpower, material resources, time, led serious economic loss, so as to avoid such problems from happening again, the corresponding countermeasures were put forward, has certain reference value and signifi- cance for similar engineering problems.