覆盖型岩溶区岩溶土洞的分布及地基处理方法

摘要

以福建龙岩市区一建筑工程项目为案例,根据工程勘察结果,分析了溶洞、土洞强烈发育的覆盖型岩溶区不均匀地基的工程特征和岩溶土洞的空间分布及稳定性,基于地基稳定性评价和验算,探索出符合当地实情的安全可靠、经济合理的岩溶区地基处理方法,即采用大直径的冲（钻）孔灌注桩或高压旋喷注浆处理,桩端持力层选用7中风化灰岩;对洞径较大、埋藏浅的土洞经直接挖开后用级配好的砂、碎石进行回填,再进行高压旋喷注浆处理;对于埋深较深难于开挖的土洞,进行预钻孔并填砂再进行旋喷处理;研究结果对岩溶地区的工程建设具有工程指导意义。%Through a construction project in LongYan City Fujian Province and based on the result of the engineering field prospection drilling,both the engineering characteristics of the non-uniform ground in buried karst region with the intensely developed karsts and soil caves and its spatial distribution and also the stability of the non-uniform ground have been obtained.After estimating and calculating the ground stability,methods of the karst ground treatment with safety,reliability,economy,reasonableness conforming to the actual situations have been obtained.The methods are as follows： pouring or drilling hole casting pile,high pressure spinning spray slip casting slurry.When the diameter of soil caves is larger and the buried depth of soil caves is shallower,the soil caves are excavated and then backfilled by crushed stones or sands with good grain series.The last treatment is carried out with high pressure spinning spray slip casting slurry.When the soil caves is buried deeply with difficulty for excavation,first pre-drill the hole,then fill in sands,and the last step is by the high pressure spinning spray slip casting slurry.The result can provide technical guidance for the engineering construction project located at buried karst region with the intensely developed karsts and soil caves.