膨胀性硅藻土的力学性质及其灾害效应研究

在云南保山－腾冲高速公路建设中，遇到了与膨胀性硅藻土相关的边坡稳定问题。通过对云南腾冲五合乡、芒棒乡、团田乡多个地质剖面现场调查和室内物质成分、微观结构分析、力学性质测试表明，云南腾冲新近纪芒棒组硅藻土是一种富含膨胀性黏土矿物的黏土质硅藻土，在性状上属于膨胀性极软岩。天然硅藻土具有很强的结构性，导致其物理性质与力学性质的关系与传统岩土力学规律极不相符，如孔隙比高达2.20～2.78、液性指数为0.66～2.73的天然硅藻土单轴抗压强度竟高达1.09～2.11 MPa。综合研究表明，云南保山－腾冲高速公路建设中黏土质硅藻土边坡的滑坡灾害、风化剥落灾害与其工程特性密切相关。

Research on mechanical properties of swelling diatomite and their geohazard effects

Slope stability problems related with the swelling diatomite are met during the construction of Baoshan-Tengchong highway in Yunnan province. After field investigation of the typical geological sections and laboratory tests of composition, microstructure and mechanical properties on the samples from Wuhe town, Mangbang town, Tuantian town of Tengchong county, Yunnan province, it is revealed that the Neogene diatomite in the Mangbang formation is a type of clayey diatomite with rich swelling clay minerals, and belongs to very soft swelling rock. Natural clayey diatomite samples have strong structural properties, which lead to the relationship between their physical properties and mechanical properties against the traditional rock/soil mechanics laws. For example, the samples have void ratio up to 2.20-2.78, liquid index 0.66-2.73, while their uniaxial compressive strength can be up to 1.09-2.11 MPa. Comprehensive researches indicate that the occurred geo-hazards including landslides and weather-flaking of clayey diatomite slope along the Baoshan-Tengchong highway are closely related to their engineering properties.