干湿循环下川东红层软岩崩解特性及量化研究

Study on the Disintegration Characteristics and Quantification of Redbed Soft Rock under the Effect of Dry-wet Cycles in East Sichuan

研究目的:针对铁路沿线红层软岩路基崩解引起的翻浆、冒泥和地基沉降等问题,以四川盆地中东部侏罗系红层软岩为研究对象,参考研究区气候环境背景条件开展了干湿循环条件下的外力扰动耐崩解性试验,通过对崩解过程进行多指标量化分析,探究干湿循环效应下红层软岩的崩解特性,明晰不同地层红层软岩的崩解差异,查明崩解速率随干湿循环的演化规律。研究结论:(1)耐崩解性试验中崩解物颗粒含量随干湿循环次数增加而呈现出的变化规律可分为粗颗粒迅速减少阶段、中间颗粒稳定阶段和细颗粒持续增多阶段;(2)不同区域的红层软岩中不同粒组颗粒含量变化和崩解性差异较大,崩解性强弱顺序为内江组>遂宁组>达州组;(3)红层软岩的崩解规律表现为随干湿循环次数的增加,耐崩解性指数、崩解比、标准基础熵不断减小,小颗粒指数不断增大;随干湿循环次数的增加崩解速率不断减小,大颗粒含量减少,同时小颗粒含量持续增多,崩解逐渐达到稳定;(4)本研究成果可为红层软岩路基的铁路选线及灾害防治提供参考及理论依据。

Research purposes:In response to the problems caused by the collapse of red bed soft rock subgrade along the railway,such as slurry,mud,and foundation settlement,the Jurassic red bed soft rock in the central and eastern Sichuan Basin was taken as the research object.Referring to the climate and environmental background conditions of the study area,an external disturbance resistance test was carried out under dry wet cycle conditions.Through quantitative analysis of multiple indicators of the disintegration process,the disintegration characteristics of red bed soft rock under dry wet cycle effects were explored,and the differences in the disintegration of red bed soft rock in different strata were clarified.The evolution law of disintegration rate with cyclic dry wet was identified.Research conclusions:(1)The variation pattern of the content of disintegrated particles with the increase of dry-wet cycles in the disintegration resistance test can be divided into three stages:the rapid reduction stage of coarse particles,the stable stage of intermediate particles,and the continuous increase stage of fine particles.(2)There are significant differences in the particle content and disintegration of red bed soft rocks in different regions,with the order of disintegration strength being Neijiang>Suining>Dazhou.(3)The disintegration law of red-bed soft rock shows that as the number of dry-wet cycles increases,the disintegration resistance index,disintegration ratio,and standard basic entropy decrease continuously,while the small particle index increases continuously.As the number of wet-dry cycles increases,the disintegration rate decreases continuously,the content of large particles decreases,while the content of small particles continues to increase,and the disintegration gradually reaches stability.(4)The research results can provide a reference and theoretical basis for railway route selection and disaster prevention of red-layer soft rock subgrade.