地震勘探在桩底岩溶探测的效果分析

Analysis of the Effect of Seismic Survey on the Prospecting of Karst at the Bottom of Piles

岩溶对工程建设的危害是非常巨大的,以桩基作为建筑物主要承载力时必须查明桩底持力层岩溶发育情况。对于已施工完成的桩基或在建桩基,抽芯发现大量持力层存在重大缺陷,普通钻探不能完全解决实际问题。结合广州花都某立交工程实例,采用管波探测法、平行地震波法、跨孔弹性波层析成像及声波透射法有机结合的方式有效查明了桩底持力层完整性情况,通过分析四种利用地震波高频成份勘探方法的频率、能量、走时及界面反射等信息,可有效探测桩底岩溶、软弱夹层等小目标地质体的分布情况。

Karst does a great harm to the construction of the project..When the pile foundation is viewed as the main bearing capacity of the building, it is necessary to find out the development of the karst bearing stratum at pile bottom. For the pile foundation that has been completed or under construction, there have been major defects in a large number of bearing layers so the ordinary drilling can not completely solve the problems. Based on an example of an overpass project in Huadu, Guangzhou, the integrity of the pile bearing layer was effectively ascertained by adopting tube wave prospecting method, parallel seismic method, cross-hole seismic method and acoustic transmission method. By analyzing the information of frequency, energy, walking time and interface reflection of four exploration methods with high frequency component of seismic waves, the distribution of small target geological bodies such as karst and weak interlayer can be effectively detected.