摘要:
基于野外调查和室内试验分析,阐述了黄土高原北部砂黄土边坡破坏的主要形式及其影响因素。结合陕北高等级公路建设,采用弹塑性有限元法模拟了不同工程开挖条件下坡形、降雨和地震作用等因素对砂黄土高边坡稳定性的影响。结果表明,随着坡角或坡高的增大,边坡稳定性不断变差,阶状坡形比一坡到顶的坡形更利于边坡稳定和防护;降雨作用对边坡稳定影响极大,在坡脚积水的情况下,坡脚处塑性应变值比常态增加近20倍;地震作用促使坡脚应力和应变值升高,并且随着地震动峰值加速度的增大而变化显著。模拟分析结果为砂黄土高边坡优化设计和灾害治理提供了科学依据。
关键词:
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砂黄土
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高边坡
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黄土滑塌
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数值模拟
Abstract:
Based on field investigation and lab tests, the main failure form of the sand loess slope and its impact factors on the northern Loess Plateau are summarized in this paper.Taking for an example from the construction of high-type highways in northern Shaanxi, a series of numerical simulations have been made using the elastico-plastic finite-element method to illustrate the influences of various factors, including the slope form, rainfall and earthquakes, on the stability of sand loess slopes under the conditions of excavation by different engineering works.The simulation results indicate that:with increasing slope angle or slope height, a slope becomes gradually less and less stable;a slope with a stepped form is more stable than that with a linear form, and is favorable for protection;rainfall tremendously influences the stability of a sand loess slope, and especially in the case of water logging at the slope foot, the stain value of the slope foot increases nearly 20 times than that in a normal state; earthquakes can make the values of both the stress and strain at the slope foot increase obviously with the growth of seismic acceleration.The simulation results provide a scientific basis for the high sand loess slope design and hazard control.
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