Mechanical Properties Of Basalt Residual Soil And Stability Analysis Of Building Slope In Qushi Ecological Town, Tengchong City

There is a layer of Quaternary basalt widely distributed in Tengchong City,Yunnan Province,China.This layer of basalt has the characteristics of late eruption age,multiple eruption periods and wide distribution range.Basalt residual soil is a loose accumulation left in place after weathering of basalt.It has the characteristics of weak to strong expansibility and large pore cohesive soil under the influence of local climate.It is easy to cause soil collapse and landslide under the condition of steep slope or terrain with certain free surface.It belongs to regional special soil and has certain hidden danger to national economic construction and people's life and property safety,which restricts the development of local engineering construction in different degrees.In this paper,the basalt residual soil formed by the weathering of Quaternary basalt in the location of Qushi town eco-tourism resort town project in Tengchong city is taken as the research object,and the mechanical properties of the basalt residual soil are studied by means of data collection,field investigation,indoor geotechnical test and field direct shear test.The results show that the thickness of the residual soil layer of basalt varies greatly,and its chemical composition is mainly Si O2,Fe2O3 and Al2O3.Its physical properties are characterized by high water content,high void ratio,low density and high compressibility.The moisture content has an important influence on its strength index.When the moisture content is high,its shear strength is obviously reduced,and the soil strength in rainy season is significantly lower than that in dry season.The basalt residual soil in Guizhou is formed by the weathering of Emeishan basalt in the Permian system.Comparing the mechanical indexes of the basalt residual soil in the study area,it is found that the basalt residual soil in the study area has the mechanical properties of large compression coefficient,large cohesion and small internal friction angle.Select a typical basalt residual soil slope in the study area,and use the test data,Sweden Arc Method and finite element software Midas / GTS NX establishes atwo-dimensional slope model to analyze the stability of the slope.The results show that: with the increase of the grid density,the stability coefficient of the calculation of the basalt residual soil slope decreases,and the calculation results are more accurate;the application of building load on the top of the slope will reduce the stability of the slope,and the geotechnical interface of the slope is most prone to sliding failure.Sweden Arc Method and finite element software are used to simulate the calculation The stability coefficient of the slope can not meet the safety coefficient,so it is necessary to reinforce the slope.In this paper,the mechanical properties of basalt residual soil are studied,and the stability of basalt residual soil slope is analyzed.The research results have important guiding significance and reference value for engineering construction of residual soil formed by weathering of Quaternary basalt in Tengchong area,and can provide basic data and theoretical basis for the follow-up study of basalt residual soil.