某既有铁路岩溶路基塌陷原因分析及整治

Cause Analysis and Remediation of Subsidence in an Existing Railway Karst Subgrade

某既有客货共线铁路一处岩溶路基出现沉陷变形,涵洞开裂,通过钻探、电测深、孔间电磁波CT等多种勘探方法,反映本段基岩岩溶强烈发育。结合现场踏勘、工点水文地质条件、覆盖层性质特点等综合分析,地表水入渗是造成本工点岩溶塌陷的主要外因。在保证既有线运营安全的前提下,设计采用洼地回填整平、加强地表截排水、基底钻孔注浆等有针对性的综合处理措施,施工完成后路基变形趋于稳定,整治效果良好。本文对厚覆盖型岩溶塌陷的机理进行了简要分析,提出了以地表水下渗为主造成岩溶塌陷的判识方法和在类似地形地质条件下路基设计应注意的问题,以供设计人员借鉴。

Subsidence deformation and culvert cracking occur in an existing passenger and freight railway line. The karst of bedrock explored by several methods such as drilling, electric sounding and Computed-Tomography between holes develops strongly in this section. The infiltration of surface water is the main reason that induces karst collapse by analyzing site information, hydrogeological conditions and layer properties. Several kinds of treatment measures such as depression backfilling and leveling, strengthening the surface drain and bore grouting in base are applied on the basis of ensuring the safety of existing lines. When the construction is completed, subgrade deformation tends to be stable, so the effect is good. In this paper, mechanism of covered karst collapse is analyzed, and the method for distinguishing the karst collapse that induced by infiltration of surface water and the design problems that should be paid attention to under similar geological conditions are put forward in order to provide reference for the designers.