吉图珲高铁延吉膨胀岩土工程特性与边坡治理研究

Research on the Engineering Characteristics and Slope Treatment of Swelling Rocks in Yanji Area on Jilin-Tumen-Hunchun High-speed Railway

以吉图珲高铁GDK279边坡为基础,进行了严寒地区膨胀岩土工程特性、边坡变形特征、滑面(带)确定、岩土参数选取等研究分析,并开展稳定性分析和工程治理对策探讨。研究表明:延吉地区膨胀岩土主要包括白垩系泥岩、泥质砂岩和夹角砾、碎石、块石及零星玄武岩孤石的第四系黏性土,黏土矿物微观结构以片状结构为主,具有中~强膨胀潜势。表层土体受长期、反复冻融循环作用,裂隙发育、结构疏松,黏性土层中夹有大量的粗颗粒角砾、碎石,成为渗水、储水构造,混合成因的各种不连续面多,不利于边坡稳定。经长期卸荷、大气降雨及风化作用,边坡沿软弱结构面或土岩界面发生滑动变形,其特征可归结为梯级牵引和多层滑动。按照“主被动支护结合、滑体疏排水与地表截排水统筹”的设计理念,进行边坡治理是行之有效的。经治理,GDK279边坡状态稳定已近十年,其经验可为同类滑坡工程治理提供借鉴。

Based on the GDK279 slope of Jilin-Tumen-Hunchun High-speed Railway,research and analysis are conducted on the engineering characteristics of swelling rock in severe cold areas,slope deformation characteristics,determination of sliding surfaces(zones)and selection of geotechnical parameters,and stability analysis and exploration of engineering governance strategies are carried out.Research shows that the swelling rocks in Yanji area mainly include two types:Cretaceous mudstone,muddy sandstone,and Quaternary cohesive soil with angular gravel,crushed stones,block stones,and sporadic basalt boulders.The microstructure of clay minerals is mainly sheet-like,with a moderate to strong expansion potential.The surface soil is subjected to long-term and repeated freeze-thaw cycles,with developed fissures and loose structures.The cohesive soil layer contains a large amount of coarse grained breccia and gravel,forming a structure of water seepage and storage.There are many discontinuous surfaces caused by mixing,which is inconducive to the stability of the slope.After long-term unloading,atmospheric rainfall and weathering,the slope slides and deforms along the weak structural surface or soil rock interface,which can be attributed to step traction and multi-layer sliding.According to the design concept of“combination of active and passive support,coordinated drainage of sliding bodies and surface interception and drainage”,the slope treatment is effective.After the treatment,the GDK279 slope has been stable for nearly a decade,and its experience can provide reference for similar landslide engineering treatment.