Research On The Effect Of Shear Strength And Structural Property And Slope Stability Of Loess Under Dry-wet Cycle

Loess is a kind of quaternary sediments. Big pore, undervoltage tightness and collapsibility are its main features. Loess has a broad distribution in our country. With the deepening of our country engineering construction, the engineering problems of loess are also revealed. Due to the alternation of seasons, the loess damage under dry-wet cycle is the main problem encountered in the engineering construction. It will cause the instability and failure of slope and roadbed. So it is particularly important to study the strength and structural change of loess after the dry-wet cycle.Through the direct shear test of loess after dry-wet cycle, to study the impact of dry-wet cycle's time and extent on loess shear strength and structural strength. The result shows that shear strength of loess samples have reduced after dry-wet cycle. Dry-wet cycle effect mainly reduces the loess cohesive force, but the internal friction angle is not affected. The more greater the dry-wet cycle range. more faster the loess shear strength decreases. The cohesive force reduces most after first dry-wet cycle. Reconstituted loess is more apparent than the undisturbed loess. The structural strength of loess gradually decreases with the increase of dry-wet cycle's time, and the more dry-wet circulation range greater, the decrease of structural strength is more obvious.Through the direct triaxial test of loess after dry-wet cycle, to study the impact of test water content, confining pressure, dry-wet cycle's time and extent on loess structural property.The result shows that with the increase of test water content, confining pressure, dry-wet cycle's time and extent, the loess structural reduces and stabilises eventually.SLOPE/W module in GeoStudio software is adopted to study the influence of dry-wet cycle on slope stability taking different angle and dry-wet cycle time into account. The result shows that with the increase of dry-wet cycle time, the slope safety factor decreases and the slope is inadvisable to exceed 50°.