大直径嵌岩桩残余应变状态分析

通过对2根大直径嵌岩灌注桩（人工挖孔）加载前应变状态连续监测，初步分析了桩身残余产生的原因、分布规律和对桩受力性状的影响，并得到如下结论：（1）混凝土的干缩是产生残余应变的主要因素；（2）桩身的残余应变随空间和时间变化是有规律的，但诸多施工因素（如爆破，地下水和浇注方式）会使其分布不均匀或弱化桩侧岩石的约束力；（3）桩身局部的残余应变会超过混凝土的极限拉应变而产生裂缝，失去对桩身钢筋的保护能力，并且桩身整体收缩会减小桩端与地基的接触力。以上结论可为工程实践提供参考。

Analysis of residual strain state of large-diameter rock-socketed piles

According to longtime monitor on residual strain states of two large-diameter rock-socketed cast-in-place piles (dig by hand) before loading, inducing factors and distribution rules of residual strain, and its influence on bearing behaviours of pile are analyzed, some conclusions are obtained as follows: (1) the main factor of inducing residual strain is drying shrinkage of concrete; (2) the residual strain distribution of the two piles are regularly changing with space and curing time, but some constructio...