Geochemical And Microstructure Characteristics Of Sliding Mud Of Xieliupo Landslide

Sliding mud, the landslide product of sliding, records all information of landslide in sliding process. In the thesis, geochemical characteristic and micro structure of sliding mud in two slip zone profiles of Xieliupo landslide of Zhouqu county have been studied, including particle size, mineral and chemical composition, element species and microstructure using sieving method and optical method, XRD and XRF, Mossbauer spectroscopy and XANES, SEM, respectively. The main conclusions are as follows:(1) The content of sliding mud particle (>2mm) in Xieliupo landslide ranged from25%to50%, and meanwhile this kind of sliding mud was called gravel sand by soil classification. The soil of sliding body, slip zone and bedrock was bad gradation in both profiles.(2) In the profile Ⅰ, there were similar characteristics between the samples of sliding body and slip zone in mineral composition, both of them were rich in ankerite, and calcite was dissolved with gypsum formed; bedrock samples also had many ankerite. In the profile Ⅱ, the samples of sliding body and bedrock had more calcite, however, sliding mud had more ankerite and a little gypsum. One of the reasons of Xieliupo landslide instability was that calcite was dissolved and the shear strength of sliding mud was decreased.(3) Iron species and sulfur species revealed that the sliding body samples of profile I were similar with sliding mud in reduced condition, but the sliding body samples of profile II were in oxidation condition. The sliding mud and bedrock of both profiles were in reduced condition and oxidation condition respectively, characterized by more Para-Fe2+and sulfur in the samples, more Para-Fe3+and only sulfate in the samples, respectively. It was because the slip zone was easy to form ankerite in reduced condition and the ratio of Fe3+/Fe2+was less than1that the sliding mud was gray/black.(4) The samples of sliding body and bedrock were mainly calcite, while sliding mud was main schistose particle and layered structure, which was one of main reasons of Xieliupo landslide instability in slip zone.(5) The pore characteristic of sliding body was different from sliding mud’s, the pore of parallel sliding plane of sliding mud closed to round and vertical section’s was long and narrow. In the profile Ⅰ, area fraction varied in complex revealed sliding mud self-complexity. In the profile Ⅱ, area fraction was decreased along profile from sliding body to bedrock. The minimize of sliding mud area fraction reflected near sliding plane, which was similar with the minimize of frequency curve’peak, revealed the period of forming time of slip zone to some degree.