西北地质2024，Vol.57Issue(2)：262-274,13.DOI:10.12401/j.nwg.2023164
川西泸定昔格达地层黏土岩工程地质特性研究
Engineering Geological Characteristics of Xigeda Formation Claystone in Luding County,Western Sichuan
摘要
Abstract
The Xigeda Formation is a special semi-diagenetic,which has the characteristics of"wind-induced powder,water-induced mud",and is a good carrier for engineering geological problems and geological hazards.In this study,the yellow and gray claystone of the Xigeda Formation in Haiziping Village,Luding County,west-ern Sichuan was investigated.Its material composition,microstructure,and mechanical properties were ana-lyzed by X-ray diffraction(XRD),scanning electron microscopy(SEM),field and laboratory geotechnical tests.The variation law of its physical and mechanical properties under the action of water is emphasized,and the en-gineering geological characteristics of the Xigeda Formation are compared and analyzed with those in other re-gions.Based on the above research,some conclusions are as follows.①The Xigeda Formation claystone in Haiziping Village is mainly composed of fine sand,clay,and additional fine-grained materials.It is produced by yellow and gray thin layers interbedding and has a horizontal lamination structure.②Yellow and gray claystone have the same material composition,but material proportions are different.The clay content of yellow claystone is 12%higher than that of gray claystone,and the calcite content is 10%inferior.The microstructure of yellow claystone is denser and cemented with clay particles more strongly.③The permeability coefficient measured on the site of Xigeda Formation claystone in Haiziping Village is 3.62～7.34×10-4 cm/s,which is between clay-stones and sandstones in Xigeda Formation in other regions.The characteristic of its permeability is closely re-lated to the development of natural joints and the characteristic of cracks that is susceptible to disturbance.④The cohesion of yellow and gray claystone decreased with the increase of moisture content,and the higher the moisture content,the greater the decline,but the relationship between internal friction angle and moisture con-tent was different.⑤ The mechanical properties of the Xigeda Formation in different regions and lithology have obvious differences in sensitivity to moisture content changes,among which the mechanical property weaken-ing by the water of the Xigeda Formation claystone in Haiziping Village,Luding County is the most significant.关键词
昔格达地层/黏土岩/微观结构/工程地质特性/川西地区Key words
Xigeda Formation/claystone/microstructure/engineering geological characteristics/Western Sichuan分类
天文与地球科学引用本文复制引用
李祥,吴瑞安,郭长宝,倪嘉伟,王炀,李彩虹,宋德光..川西泸定昔格达地层黏土岩工程地质特性研究[J].西北地质,2024,57(2):262-274,13.基金项目
国家自然科学基金项目"构造缝合带蚀变软岩强度劣化效应及其对巨型滑坡的控滑机理"(42207233),中国地质调查局项目"全国重大工程地质安全风险区划与综合评价"(DD20221816),国家重点研发计划项目课题"地质灾害云-端协同智能预警系统构建与示范应用"(2021YFC3000505)联合资助. （42207233）
