本文選題：降雨 + 入滲��； 參考：《浙江大學(xué)》2014年碩士論文

【摘要】：近年來,降雨入滲導(dǎo)致邊坡失穩(wěn)的情況越來越多,這是由于雨水入滲后破壞了邊坡的應(yīng)力平衡體系。降雨對邊坡產(chǎn)生作用的機理主要在兩方面：一是降雨動能外部的作用,二是降雨入滲后坡體內(nèi)部產(chǎn)生的有關(guān)作用。以前只注重前者,對于后者研究較少,但這種作用往往是非常重要的。同時,降雨入滲和邊坡破壞是一個不斷隨時間持續(xù)變化的過程,其受土體類型及性質(zhì)、雨型及雨強、邊坡構(gòu)造形狀、地下水及人類工程活動的影響。針對這一情況,本文從外在因素(降雨形式、初始含水率、氣阻分層)和內(nèi)在因素(邊坡傾角、斜邊形狀、飽和導(dǎo)水率)的角度對邊坡入滲特性和穩(wěn)定性的影響進(jìn)行了詳細(xì)分析。 首先介紹了非飽和土的概念及其入滲理論,分別闡述了Green-Ampt模型、Horton模型、Philip模型、Kostiakov模型的基本假設(shè)和使用條件,重點介紹了Bishop和Fredlund非飽和土抗剪強度公式以及兩者之間的區(qū)別,之后闡述了非飽和土穩(wěn)定性分析特點和極限平衡分析方法。 本文側(cè)重探討了變雨強強度下邊坡入滲特性與常降雨強度的差異,以及飽和導(dǎo)水率、土壤類型在變雨強下的敏感性分析；推導(dǎo)了初始含水率線性和任意函數(shù)分布下的濕潤鋒隨時間的變化關(guān)系,并將線性分布下的函數(shù)關(guān)系帶入邊坡安全系數(shù)公式中進(jìn)行了穩(wěn)定性分析；討論了分層假定的入滲量修正和氣阻作用Green-Ampt模型的入滲率修正,并運用其修正結(jié)果分析了入滲時間和濕潤鋒深度的變化關(guān)系：分析了積水條件和降雨條件下傾角對邊坡入滲和穩(wěn)定的敏感性,將濕潤鋒和時間變化關(guān)系無量綱化,并應(yīng)用于邊坡安全性分析中；求解了梯田在灌溉條件下邊坡潛在滑裂面的位置,并與斜坡同一時刻下的安全性作了對比；假設(shè)了飽和導(dǎo)水率沿豎向指數(shù)、線性、冪次變異情況下,入滲率的表達(dá)式及濕潤鋒和時間的變化關(guān)系,并分析了入滲偏差較小的指數(shù)和冪次變異下的邊坡安全系數(shù)。研究表明,不管外在因素(降雨形式、初始含水率、氣阻分層)還是內(nèi)在因素(邊坡傾角、斜邊形狀、飽和導(dǎo)水率)對入滲和邊坡穩(wěn)定都有明顯影響,加強這方面的分析對了解邊坡入滲內(nèi)部運動和準(zhǔn)確把握邊坡失穩(wěn)有重要意義,從而適時采取有效的防護(hù)措施。
[Abstract]:In recent years, more and more slope instability is caused by rainfall infiltration, which is due to the failure of the slope stress balance system after Rain Water infiltration. The mechanism of rainfall acting on slope mainly lies in two aspects: one is the external effect of rainfall kinetic energy, the other is the related effect of slope body after rainfall infiltration. Previously only the former, for the latter less research, but this role is often very important. At the same time, rainfall infiltration and slope failure is a process of continuous change with time, which is influenced by soil type and property, rain type and rain intensity, slope structure shape, groundwater and human engineering activities. In this paper, the external factors (rainfall form, initial moisture content, air resistance stratification) and internal factors (slope inclination, slope shape) and internal factors (slope angle, slope shape) are analyzed in this paper. The influence of saturated water conductivity on slope infiltration characteristics and stability is analyzed in detail. Firstly, the concept of unsaturated soil and its infiltration theory are introduced. The basic assumptions and application conditions of the Horton model and the Philip model and the Kostiakov model of the Green-Ampt model are expounded respectively. The shear strength formulas of Bishop and Fredlund unsaturated soils and the difference between them are introduced. Then, the characteristics of unsaturated soil stability analysis and limit equilibrium analysis method are described. In this paper, the difference between the infiltration characteristics of slope and the intensity of constant rainfall, and the sensitivity analysis of saturated water conductivity and soil type under variable rainfall intensity are discussed. The variation of wetting front with time under linear and arbitrary function distribution of initial moisture content is deduced, and the function relation under linear distribution is introduced into the formula of safety factor of slope for stability analysis. The infiltration rate correction of the stratified assumption and the gas resistance Green-Ampt model is discussed. The relationship between infiltration time and depth of wetting front is analyzed by using the modified results. The sensitivity of dip angle to slope infiltration and stability is analyzed under the condition of water accumulation and rainfall, and the relationship between wetting front and time is dimensionless. It is applied to slope safety analysis, the location of potential slip surface of terrace under irrigation condition is solved, and compared with the safety of slope at the same time, the saturated water conductivity is assumed to be linear along the vertical exponent. Under the condition of power variation, the expression of infiltration rate and the relation between wetting front and time are analyzed, and the slope safety factor under the condition of low infiltration deviation and power variation is analyzed. The results show that whether external factors (rainfall form, initial moisture content, air resistance stratification) or internal factors (slope angle, slope shape, saturated water conductivity) have a significant impact on infiltration and slope stability. Strengthening the analysis in this respect is of great significance to understand the internal movement of the slope infiltration and accurately grasp the slope instability, so as to take effective protection measures at the right time.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TU43

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本文編號：2021714