Analysis Of Expansion Characters And Determination Calculation Of Shear Strength Of Swelling Rocks

Swelling rocks are so easily worn away by wind and softened that it belongs to soft rocks, it has the character swell when watered and shrink when dried out. Because of complexity of physical and mechanical properties, mechanism of intumescence and directional distribution, swelling rocks has been one of the hardest studies in the field of engineering geology and rock mechanics. The length of swelling rocks along the middle route of the South-to-North water diversion project area is about several kilometers. Steady of canal slope is often weakened by the rocks, which endangers safety of the project and becomes one of main technical matters. It isvery necessary and urgent to lucubrate expansion character and to search after a comprehensive evaluation model and a analysis on determining the values of strength parameters. In this paper, expansion character and determining the values of strength parameters of swelling rocks are discussed as below:1. Factor analysis of expansion character of swelling rocks. By way of partial correlation, stepwise regression analysis and principal component analysis, the relation between swelling indexes including expansibility, free swell and physical mechanics property indexes containing liquid water content, dry density, liquid limit, plastic limit, clay content, colloid content was researched, then the most representative physical mechanics property indexes were determined following the fitted formula.2. The comprehensive evaluation model of expansive potentia. Based on the analysis of expansion character, a comprehensive evaluation model of expansive potential was built up. The suggestive values of the four indexes under different expansive potential were listed and range values of indexes were counted.3. Impact analysis of the depth of the earth's atmosphere to expansion character. The value of the depth of the earth's atmosphere was determined. Correlation analysis between swelling indices and physical mechanics property indexes was done, the rule of swelling rocks adjusting to depth was researched to provided a reference to determine the values of strength parameters of swelling rocks using the way of hierarchical sub-band.4 A study of determining the values of strength parameters of swelling rocks. Based on the statistical analysis of the data of strength parameters during the early exploration, probability distribution of shear strength parameters was studied, and sensitivity analysis between shear strength parameters and free swell, depth, liquid water content were also done in the case of natural fast-shear test,saturated fast-shear test and saturated consolidation quick shear test. Finally suggestion of determining the values of strength parameters of swelling rocks was presented.