钻孔灌注桩桩底溶洞声呐探测方法及应用研究

A sonar detection technology for karst cavities under bored piles and its application

钻孔灌注桩桩底溶洞的存在给在建工程和周围建筑造成重大影响。由于钻孔灌注桩需要泥浆护壁,现行的物探方法很难在钻孔灌注桩的泥浆内对桩底溶洞进行有效勘查。结合声呐应力波传播特点,提出一种钻孔灌注桩桩底溶洞声呐探测方法,并研发桩底溶洞声呐探测仪(JL-SONAR)和信号分析软件(PBCA)。JL-SONAR探测仪实现了现场声呐信号的发射与采集,PBCA软件完成了探测数据的分析与整理。该技术充分利用钻孔灌注桩的泥浆条件,可以在成孔过程中跟踪探测桩底10 m内溶洞发育情况,具有成本低、速度快、精度高等优点。并通过2个具体工程案例验证了声呐探测技术在实际工程中的应用。研究成果对岩溶地区尤其是液态环境下的溶洞勘查提出了一种新的解决方法。

Those karst cavities beneath the bottom of cast piles in bore hole have significant impact on the project itself and the surrounding buildings. Due to the necessary mud protection in bored pile construction,many geophysical methods at current stage are not applicable for the karst cavity detection. A sonar technology for the detection of karst cavities located beneath the bored pile was proposed utilizing the features of sonar stress wave propagation. A sonar detector（JL-SONAR） and a signal analysis software PBCA were developed. JL-SONAR detector was responsible for the transmission and collection of sonar signals,and PBCA software was designed to analyze and sort the detection data. The technology makes full use of drilling mud,and enables the detection of the karst cavities within the range of 10 meters below the pile bottom during drilling. The technology was applied in two projects successfully and has the advantages of low cost,high speed and high precision.