|
Earthquake landslides and earthquakes are common secondary disasters, with its huge hazard force aroused widespread concern. In mountainous areas, earthquake-induced landslides, avalanches and other disasters with large, wide range of features, often more than the losses caused by the earthquake itself. Study area belongs to the western mountainous terrain, terrain complexity, relative height, steep terrain. Region complex lithology, faults developed by Longmen central fault and piedmont fault affecting the study area geological phenomenon quite developed. In this thesis, system engineering geology research methods, detailed knowledge of the regional geological structure in the environment and the geological structure of the study area, the environment, based on the study area to conduct a detailed investigation of geological disasters, through field survey of a large number of various types of geological disasters distribution under analysis and found that many small and medium-scale disaster points, concentrated in the 800 ~ 1200m and densely distributed between the central and piedmont fault rupture near the farther away from the fault, the less disaster-density development. Then the typical formation mechanism of geological hazards research. After the study found topography, lithology, geological structure and the impact of seismic force caused by earthquake landslides and other geological disasters have a great impact. Peak ground acceleration big place, seismic landslide density, disaster earthquake acceleration small number of points over the place, so earthquakes are a large number of geological disasters cause the most immediate and most critical factor is the external cause geological disasters, topography, stratigraphy lithology, geological structure is internal. Distribution and geological disasters in the formation mechanism and the main factors based on the analysis, this paper studied the earthquake, the different slope morphology, different slope types, different aspect, slope height under different slope soil ground motion response. Role in the high-intensity earthquake (Ⅷ above), the concave slope PVIs will appear slightly larger on the location of the deformation, the slope of the inflection point maximum shear strain; inclined slope with the slope than the reverse tilt poor stability; seismic force, slope orientation and seismic wave propagation in the same direction, disaster aggravation; slope height is less than 100m, moving around 1.1g peak acceleration in general, terrain amplification effect is not obvious, 100 ~ 200m office, moving peak acceleration generally about 1.5 ~ 1.7g, topographic amplification effects are obvious. In the earthquake, the different types of rock structure, different terrain, different aspect, a different angle seismic waves, the different types of lithology and slope of slope rock ground motion response, and compete with different slopes and different slope boulders on the slopes ground motion response. Rock structure, fragmentation structure, layered structure and bulk structure affected by the earthquake the largest and most prone to collapse and landslides; slope orientation and seismic wave propagation in the same direction, damage increased; seismic wave incident angle less than the critical angle When the surface structure of a point shear failure occurs first, with the crack extends along the structural surface slope instability failure; slope height is different, the terrain amplification effect was also significantly different slope height is less than 100m, its terrain amplification effect is not obvious, 100 ~ 200m, terrain amplification effect is obvious, dynamic peak acceleration concentrated in the 1.3 ~ 1.5g, higher than 200m, moving more than 1.6g peak acceleration in general; when alternating hard and soft rock, easy to form a weak surface or sliding surface, if the ramp is down-dip slope under earthquake are more prone to landslides. Then AHP geological disaster situation assessment and predictive analysis in the study area were integrated geological hazard assessment is divided into five regions, and proposed control measures, construction of the study area has a reference.
|