单桩静载试验的桩顶沉降稳定收敛特征研究

采用单桩静载试验,系统地对36根工程桩的324个荷载级进行沉降稳定分析和荷载稳定时间分析,并通过中等直径灌注桩和超长大直径嵌岩桩两种桩型的15根单桩进行了对比分析。研究表明:不论是嵌岩桩还是非嵌岩桩,各级荷载总体都在1小时内稳定且占比高达96.3%;桩顶的沉降速率、加速度均表现出随时间衰减的特征,证明了桩顶位移具有基于时间、位移的收敛的性特征,且试验耗时降低40%以上。采用P-s曲线法、LogP-s曲线法、E-Δs/ΔQ法判定了单桩的极限荷载,验证了桩顶沉降值在合理的范围之内,同时也表明对桩顶沉降收敛特征的研究可以有效的缩短桩基础检测的时间并提高检测效率。

The Stabilized Convergent Characteristics of Pile Top Settlementin Single Pile Static Loading Test

The settlement stability analysis and load stability time analysis were carried out systematically for 36 engineering piles with 324 load levels using single pile static load test, a comparative analysis of 15 engineering piles of medium-diameter cast-in-place piles and super-long large-diameter rock-stocked piles was carried out. The study shows that: whether rock-socketed piles or non-rock-socketed piles, all levels are generally stable within 1 hour and the proportion is as high as 96.3%; the settlement rate and acceleration of pile top show the characteristics of decay with time, which proves that the pile top displacement has the characteristics of displacement convergence, the static load test time might reasonably reduce 40% or more. The P-s curve method, LogP-s curve method and E-Δs/ΔQ method were used to determine the ultimate load of the single pile, which verified that the settlement value of the pile top was within a reasonable range, and also showed that the study of the convergence characteristics of the pile top settlement could effectively shorten the time and improve the efficiency of the pile foundation inspection.