摘要
灰绿色、红色泥岩在干旱或半干旱气候条件下形成,富含黏土矿物,遇水后物理力学性质发生显著变化,对工程建设的安全有重要影响,对其物理力学特性开展研究在地质灾害防治和工程设计施工中都具有重要意义。不同泥岩具有不同的物理力学性质,为进一步研究其差异,对甘肃省天水秦州区西河乡灰绿色泥岩以及天水花南村滑坡(310国道K1428+200段)滑带处红色泥岩进行了基本土工试验、矿物成分分析、易溶盐成分分析以及高含水率下的直接剪切试验。研究发现灰绿色泥岩级配更好,且含有较多的黏土矿物,而红色泥岩则含有较多的石英及原生矿物,二者的黏土矿物都以伊利石为主,高岭石次之,蒙脱石含量较少。2种泥岩遇水后都溶解出较多的Na^+,K^+,3HCO-以及少量的Ca^(2+),使土体颗粒水膜增厚,带电分子间的引力减弱,黏结力降低,并使矿物更易遭受破坏,灰绿色泥岩溶于水后的易溶盐总量相对较多。在高含水率情况下,2种泥岩的抗剪强度参数都随含水率及干密度发生变化,灰绿色泥岩的抗剪性能明显优于红色泥岩。当含水率达到25%时,红色泥岩抗剪强度较绿色泥岩显著降低,含水率超过30%后,二者都基本丧失抗剪能力。
Mudstone is a kind of soft rocks containing abundant clay minerals. The physical and mechanical properties change drastically when mudstone encounters water. Studies on the green and red mudstones from Tianshui, Gansu province were carried out. The experiment results show that the green mudstone contains more clay, while the red one has more primary minerals. The main clay mineral in both types of mudstones is illite, and there are less kaolinite and little montmorillonite. When the two kinds of mudstones interact with water, a lot of Na^＋, K^＋, HCO3^- but little Ca^2＋ are dissolved out. As a result, the thickness of the bound water membrane increases, the attraction between the electrically charged molecules decreases, the adhesion force diminishes and the minerals are much easier to be eroded. The results also indicate that under the condition of high water content, shear strength parameters of both mudstones change with the variation of water content and dry density, but the shear strength of green mudstone is better than the red. When the water content increases to 25%, the shear strength of red mudstone declines dramatically. And when the water content is over 30%, both type ofmudstones almost lose the shear strength.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2016年第12期2572-2582,共11页
Chinese Journal of Rock Mechanics and Engineering
基金
国家重点基础研究发展计划(973)项目(2014CB744701)
国家自然科学基金资助项目(41362014)~~
关键词
岩石力学
灰绿色泥岩
红色泥岩
可溶盐分析
矿物成分
抗剪强度
rock mechanics
green mudstone
red mudstone
analysis of soluble salt
mineral component~ shearstrength
