摘要
四川盆地及周边山地广泛分布俗称为"川中红层"的侏罗系泥岩,是一种典型的软岩,其强度低,易风化崩解,流变特性显著,具有一定的膨胀特性,是引起该地区多处高速铁路路基长期持续性上拱变形的一个重要因素。为揭示红层泥岩在浸水条件下的时效变形特性,以川中红层典型泥岩为对象,在室内开展原状岩样浸水物化膨胀性试验,分析红层泥岩的吸水膨胀变形随时间的变化规律及其影响因素。试验结果表明,常规膨胀性指标显示川中红层泥岩为非膨胀岩,或仅具有弱膨胀性,原状岩样吸水膨胀率较小,但具有显著的时间效应;采用类Kelvin体建立红层泥岩膨胀蠕变模型,模型参数K和η可有效度量膨胀蠕变的极限应变及黏滞特性;原状岩样的结构性是影响其吸水率的重要因素,通过岩屑筛分试验获得最大含量粒组颗粒粒径dmax、细粒和微粒质量占比ω1.0和有效粒径d10三个参数,可以定量判断泥岩的吸水特性和膨胀特性,dmax越小、d10越小、ω1.0越大,则泥岩的吸水率越大,膨胀性越强。研究成果对川中红层泥岩地层高速铁路路基长期持续性上拱变形的机制认识及治理方案论证具有参考作用,并为红层泥岩物理、水理及力学特性及其相互关系的定量研究提供基础。
The Jurassic red-bed mudstone,widely distributed in Sichuan basin and the peripheral mountains and named as Sichuan Central Red-bed,is a typical kind of soft rock with low strength,easily weathering and disintegrating,notable rheology and slightly swelling,and taken as one of the most important factors resulted in the upheaval deformation of some high speed railway subgrade sections. In order to reveal the time-dependent swelling characteristics of red-bed mudstone under soaking condition,the expansion tests were carried out on typical Central Sichuan red-bed mudstone samples,and the hydrophil expansion deformation of red-bed mudstone with time and the influence factors were analysed. The results show that as indicated by the conventional swelling index,the selected red-bed mudstone is non-swelling or weakly swelling, and that the water-absorption expansion rate is low but time-dependent significantly. A swelling creep model of red-bed mudstone was proposed based on the Kelvin system,in which the creep parameters,K and η,can effectively quantify the ultimate swelling strain and viscous properties during creeping,respectively. The structure of undisturbed rock samples is an important factor influencing the water-absorption. The grain size of the maximum content group,dmax,the weight ratio of fine and micro particles,ω1.0,and the effective particle size,d10,obtained through the sieve tests,can quantitatively evaluate the water-absorption and swelling characteristics of red-bed mudstone. The smaller dmax and d10,the larger ω1.0 is and as a result,the water-absorption and swelling are stronger. The research work can provide a reference for revealing the long-term upheaval mechanism and demonstrating the treatment scheme of high speed railway subgrade Sichuan Central red-bed mudstone,and also laid a basis for the further quantitative research of red-bed mudstone on the physical,hydraulic and mechanical properties and their relationships.
作者
钟志彬
李安洪
邓荣贵
吴沛沛
徐骏
ZHONG Zhibin;LI Anhong;DENG Ronggui;WU Peipei;XU Jun(China Railway Eryuan Engineering Group Co.Ltd.,Chengdu,Siehuan 610031,China;School of Civil Engineering,Southwest Jiaotong University,Chengdu,Siehuan 610031,China)
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2019年第1期76-86,共11页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(41272321
51808458)
中国博士后科学基金资助(2018M640934)~~
关键词
岩石力学
红层泥岩
膨胀
蠕变模型
吸水率
原状岩样结构性
rock mechanics
red-bed mudstone
swelling
creep model
water-absorption rate
structure of undisturbed rock samples
