For the multiformity

complexity of the slide zone clay and unequal of the shear strength parameters in the Three Gorges Reservoir area

the main factors affecting the shear strength parameters including geological representation

specimen size

test number

stress level are reseached

especially for the unequally shattered clay and silty clay

those factors may bring out much more influence. The characters of the slide zone are changed with the different places. The two groups test between the different places and the same characters of the slide zone show that the shear area should be no less than 2 500 cm2

otherwise the shear strength parameters (c

?) are much unequal. The three groups tests in the same place

5 or 6 points a group

show that the shear strength parameters (c

?) have 0.5-1.0 time difference

and show that the test number in a group should be no less than 5 points; the contrast test under the different moisture content shows that the moisture content is more

and the parameters (c

?) is littler. For the unequal characters of the shattered clay and silty clay

the granules diameters and content of the crushed stone also affect the shear strength. So

tester must sechedule reasonable test scheme according to code

project character

and environment of the slide zone

analyze the parameters according to macroscopical characters of slide zone and actual conditon of test point

then put forward proposition parameters.