应用超声波与芯样强度对旧桥桩底基岩完整性评价

摘要

The integrity of pile foundation rock is an important indicator for bridge durability and safety,especially for the bridge foundation in karst area.In order to evaluate the stability and durability of bridges under operation,it is required to detect the integrity and bearing capacity of pile foundation rock.In this paper,with the theory that waveform will be distorted for the speed and propagation time are affected by fissure and pit mud in bedrock,the integrity of pile foundation rock of bridges under operation in karst area is evaluated.By drilling holes based on equilateral triangle around pile and using ultrasonic detection technology,combined with indoor test on core sample,the integrity and bearing capacity of pile foundation rock are evaluated.Through detection of Bajiang Bridge,this method is proven feasible,and thus the durability and safety of bridge pile foundation can be estimated thereof.%桩底基岩的完整性是桥梁耐久性和安全性的重要参数,尤其是岩溶地区的桥梁基础。为评价运营期桥梁的稳定性及耐久性,需对桩底基岩的完整性、承载力进行检测。利用超声波在基岩中传播时,其波速、传播时间受裂隙、夹泥等缺陷的影响,波形会发生畸变的原理,对岩溶地区营运桥梁桩底基岩的完整性进行评价。先在桩周呈等边三角形分布钻孔,再利用超声波检测技术,结合所取芯样进行室内试验,来评价基岩的完整性和承载力。通过巴江河特大桥检测证明,该法是可行的,进而判断桥梁桩基的耐久性与安全性。