巨型溶洞区深厚填筑体长期变形特性试验研究  

Experimental Study on Long-Term Deformation Characteristics of Deep and Thick Fills in Giant Karst Cave

作　　者：苏芮 苏谦[1] 贺琛方 董敏琪 王迅[1] 郑余朝[1] SU Rui;SU Qian;HE Chenfang;DONG Minqi;WANG Xun;ZHENG Yuchao(School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China)

机构地区：[1]西南交通大学土木工程学院,四川成都610031

出　　处：《西南交通大学学报》2024年第6期1487-1496,共10页Journal of Southwest Jiaotong University

基　　金：国家自然科学基金项目(51978588)。

摘　　要：为探讨不同深度位置溶洞回填体与天然堆积层的沉降和应力随时间的变化规律,以成贵铁路玉京山隧道大型溶洞回填工程为原型,开展1∶100的室内离心模型试验,对溶洞大厅底部不均匀天然软弱堆积层长期变形规律进行分析,采用粒径小于2 mm的河沙模拟废弃洞渣回填体,使用川西黏土模拟溶洞底部软土层,并用现场监测结果验证室内试验可靠性.研究结果表明:施工结束后1.5年,溶洞回填体变形基本达到稳定状态,且变形量约为总沉降量的86.9%;软土层的变形是隧道底部土体变形的主要组成部分,其变形量约占总沉降的87.5%;隧底沉降量与底部软土层厚度成正相关,并且当软土层厚度小于12.5 cm时,软土层厚度对隧道底部沉降影响较小;模型试验沉降变形与现场监测结果相差为3.83%,表明本文所开展试验能够反映出隧道底部土体长期变形特性.In order to explore the variation of settlement and stress of the karst cave backfill and natural accumulation layer at different depths,a giant karst cave backfill project in the Yujingshan tunnel of Chengdu—Guiyang railway was studied.A 1∶100 laboratory centrifugal model test was carried out to analyze the long-term deformation law of the inhomogeneous natural soft accumulation layer at the bottom of the karst cave,in which the river sand with a particle size of less than 2 mm was used to simulate the karst cave backfill,and the western Sichuan clay was used to simulate the soft soil layer at the bottom of the karst cave.The reliability of the laboratory test was verified by field monitoring results.The results show that the deformation of the karst cave backfill basically reaches a stable state within 1.5 years after the termination of construction,and the deformation is about 86.9%of the total settlement;the deformation of the soft soil layer is the main component of the soil deformation at the bottom of the tunnel,and its deformation accounts for about 87.5%of the total settlement.The settlement at the bottom of the tunnel is positively correlated with the thickness of the soft soil layer,and when the thickness of the soft soil layer is less than 12.5 cm,it has less influence on the settlement at the bottom of the tunnel.The difference in settlement deformation between the model test and the on-site monitoring is only 3.83%,indicating that the experiments conducted in this article can reflect the long-term deformation characteristics of the soil at the bottom of the tunnel.

关 键 词：深厚填筑体 长期变形 离心模型试验 软土层不均 现场监测 

分 类 号：U25[交通运输工程—道路与铁道工程]