Deformation & Failure Characteristics of Rock Slope
Before rupture surface appearing in rock slope, its change characteristics belong to deformation characteristics and after penetrating rupture surface appearing, it belongs to failure characteristic. Its development processes are: loose or tension crack, rock mass creep, accelerated creep and failure. The first three steps are deformation characteristics and the last step is failure characteristic.
1. Deformation characteristic.
At the beginning stage of slope forming, because of unloading function, stress in rock body redistributed, which makes slope surface and surrounding rock loss, then surface will be cracked, including spring back fissure, tensile fracture belt at slope surface and slope term cracks, fracture brought by stress concentration at slope toe.
After rock slope happening loose, it reduces rock body’s strength. Under external force (mainly self weight), rock mass becomes slow deformation to free surface, which is called rock slope’s creep. If stress in slope is smaller than long-term strength of rock body, creep of slope will decelerate gradually; on the contrary, if slope creep accelerates, it will finally cause failure.
2. Failure characteristic.
Owing to various reasons of slope failure, and after failure, its forms and functions are inconsistent, the classify of slope failure form is various. From perspective of mechanical characteristics of failure, common slope failure form can be divided into rock collapse, translation slide, rotate slide, rock flow and rock stratum twist and turn.
Self drilling anchor is a supporting method with good effect. At deformation stage, full grouting can fill stratum cracks sufficiently to prevent further failure.