The Temperature Effect Of Rock Structure Weathering Front Expanding Process Under The Non-saturated Zone Environment

Mainly aims at the rock structure in problem of coupling on the temperature and the stress, this paper investigates mechanism of rock structure weathering front expanding when rock suffers temperature of non-saturated zone environment. With major rock thin-section authentication, scanning electron microscope, rock complete analysis of test methods. From the theoretical and numerical simulation to research to analysis of temperature stress on the rock structure of the damage mechanism which the under the non-saturated zone temperature, discussed physical weathering process on the impact of the rock structure weathering front expansion. Research results on the cause landslides, mud-rock flows and other geological disasters and engineering issues are certainly useful.Rock structure in different weathering zone, there are the obvious differences of rock and mineral structure, the structure of weathered rock near the boundary of weathered front has obvious signs of physical weathering, the process of chemical weathering rarely participate in. Numerical analysis show that, different types of rocks structure is very close to temperature of the conduction patterns, heat along the rock structure in the direction of the normal inward transfer, the form of heat diffusion from two sides opposite sides, which gradually heat transfer angular passivation, edges and comers become more roundness, rock internal temperature gradually near circular. The analysis of temperature- coupled Stress show that, structural homogeneous of the rock material stress field in the rock structure of the internal distribution of a spherical, maximum stress gradually proliferates from the surface to inside, as for non-homogeneous materials rock structure characteristics of stress field, maximum stress from the outside to the inside of a spherical proliferation, the biggest stress present to the different media at the point of contact.Under the cyclic loading, there is a threshold value of rock damage, when cycle amplitude loading is below the threshold value, rock will not be increase of cycles times lead to destruction. Due to the temperature functionary, maximum stress will only reach or approach threshold value, under the long time of the change of entironment temperature , rock structure will be fatigue damage. Weathering front expanding form of homogeneous material rock structure is gradually extended from the outside to form a layered deformation, globular proliferation, the weathering front expansion of rock structure changes smaller. Weathering front expanding form of non-homogeneous material rock structure is gradually extended from the outside to proliferation, but due to the larger mineral composition in it, easily in the local area produced concentrated stress, leading to stress and strain become bigger within the region, easily produce fatigue damage, weathering front expanding more deeper and easily.Through analysis of weathering front expanding may indicate, the form of rock structure weathering front expanding is not just a product of physical weathering process, the formation of surface weathering front is temperature effect procreant stress make rock from larger particles to the small grains, formed loose "cavernous" Structure, settle the base for vapor diffusion, conducive to the conduct of chemical weathering, chemical weathering make the rock structure to soil finally, in this sense that, physical weathering of the rock weathering is the precursor and the necessary conditions , chemical weathering is the continuation and deepening of weathering. And in fact, weathered rock structure of the process is an extremely complex THMC ( coupled thermo-hydro-mechanical- chemical processes ) multiple roles under the coupling process, physical and chemical weathering in nature often at the same time, the mutual influence and promote each other.