| Bank collapse is a common natural phenomenon and it is one of major disasters on both sides of widespread alluvial plain rivers, the frequency of its occurrence is more frequent and serious. In addition, the water level affects the stability of the embankment landing on water conservancy sector and geotechnical engineering is a very important and difficult problem. During the high water, the shear strength of the embankment soil decreases due to saturated when the water level dips. When the water level drops suddenly, not only acting on the water pressure of the beach can not provide support for the role of the bank, and will produce a unsteady seepage that adverses to the slope stability, resulting in the formation of seepage pressure and pore water pressure. They all will endanger the stability of the slope. Therefore, in terms of classification and influence factors of bank collapse, the research on the mechanism may have theoretical and practical significance of the flood control and disaster and river regulation.Based on the collecting and analyzing the former research results and generalized model, different classifications, influencing factors and stress characteristic of different soil riverbank are summarized. The key research is the stability of riverbank under drowning conditions, and the sensitivity analysis about influencing factors of bank collapse are made. In the end, the forecast and control of bank collapse are recommended. The main research results are as follows:1. Different classifications and characteristics are summarized and the influencing factors of are analyzed in detail to explore the causes and patterns of bank collapse.2. The different riparian composition, soil starting stress characteristics of different kinds of riverbanks and the condition and method of different bank failure are specific analyzed.3. Using limit equilibrium method analyses the impact of water level near river and groundwater level difference, water erosion and underground water level of river bank slope stability. The main conclusions are:(1) Whether under undisturbed river bank or water erosion effect, water levels near river and groundwater levels have a certain influence on the stability of the river bank slope. Early recession of water, riparian slope stability safety factor declines the fastest, with the continued decline in the water level, riparian slope stability gradually stabilized.(2) The lateral and vertical water scouring will promote the collapse of the river bank slope. The erosion of riverbed and riverbank is more intense, river bank slope is unstable, the more prone to bank collapse.(3) When groundwater level is a constant, slope stability factor gradually increases with the increase of water level near river. On the contrary, slope stability factor will be smaller and smaller with the decrease of water level near river.4. Using the single sensitivity analysis formula, systematically analyze the impact of cohesion, internal friction angle and the groundwater level on the slope stability. The main conclusions are as follows:(1) Cohesion c is the strongest affecting factor for the bank slope stability, and thsensibility increases with slope angle and with the increase of groundwatlevel.(2) Groundwater level Hd is the stronger affecting factor for the bank slope stability, and the sensibility decreases with the decrease of cohesion and with the increase of internal friction angle.(3) Internal friction angle φ has a smaller effect for the bank slope stability, and the sensibility increases with with the increase of cohesion, and with not obvious variation of the sensibility when groundwater level changes.5. May predict and governance principles and method are introduced, which focus on characteristics and application of tetrahedron-like concrete penetrating frames in bank protection. |
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