The sliding zone is an important part of landslide

and its intensity and deformation parameters have important effect on the slope stability.On the influence of the change of reservoir water level and rainfall in the Three Gorges reservoir area

the water content in the sliding soil is changed

that makes the strength and deformation modules of sliding soil change with the changing of water content.Taking the sliding zone of Sanzhouxi landslide as an example

The undrained shear test and compression test for different water contents of sliding zone are done.The composition and the microstructure of mineral are studied by X ray diffraction analysis and electron microscope scanning

and the slope stability are studied.The results show that

the sliding soil contains large amount of montmorillonite mineral

with strong hydrophilicity and obvious directional arrangement.The micro cracks and pore in the mineral are developmental.The shear strength

deformation modulus and slope stability are sensitive to the change of water content in the sliding zone.The optimum water content is put forward.With the increasing of water content

the cohesion c firstly increases and then reduces

the internal friction angleφdecreases firstly slowly and then rapidly

and the deformation modulus decreases firstly rapidly then slowly.The slope stability factors firstly increase and then decrease

and the location of sliding surface is changed from deep to shallow with water content.The result has benefit to the slope stability.