本文選題：冰磧物 + 飽和-非飽和　； 參考：《成都理工大學(xué)》2014年碩士論文

【摘要】：孟底溝壩前堆積體的穩(wěn)定性對(duì)孟底溝水電站安全修建和運(yùn)營有著至關(guān)作用和影響。通過現(xiàn)場(chǎng)詳細(xì)的地質(zhì)勘察,調(diào)查該工程區(qū)的工程地質(zhì)特征,分析堆積體的空間展布、結(jié)構(gòu)特征、地質(zhì)成因,從整體上對(duì)孟底溝壩前堆積體作定性的判斷。在整體認(rèn)識(shí)的基礎(chǔ)之上利用室內(nèi)試驗(yàn)獲得基本物理力學(xué)參數(shù)。由于壩前堆積體的工程特性,降雨和庫水位變化時(shí)是對(duì)其穩(wěn)定性影響最大的因素,本文運(yùn)用飽和-非飽和土理論對(duì)孟底溝堆積體在不同降雨方案下和不同的庫水位上升速率的條件下其滲流場(chǎng)特征進(jìn)行全面的分析,得出孔隙水壓力、體積含水率的變化規(guī)律,繼而利用極限平衡法計(jì)算分析降雨、庫水位變化對(duì)孟底溝堆積體穩(wěn)定性的影響,這對(duì)工程建設(shè)是有指導(dǎo)性作用的。圍繞堆積體的滲透特征和穩(wěn)定性為中心,本文得到以下認(rèn)識(shí)： 1.通過對(duì)堆積體所在地區(qū)地質(zhì)歷史、地形地貌特征、堆積體顆粒組成及結(jié)構(gòu)特征等的調(diào)查分析,可以認(rèn)為該堆積體應(yīng)屬我國西部地區(qū)末次冰期冰川運(yùn)動(dòng)遺留的冰磧堆積體。 2.通過室內(nèi)大剪試驗(yàn)、大三軸試驗(yàn)、滲透試驗(yàn)獲得了堆積體的天然和飽和抗剪強(qiáng)度指標(biāo)、滲透系數(shù),并提出了堆積體土樣強(qiáng)度參數(shù)建議值。 3.降雨工況下,通過不同的降雨方案,同時(shí)考慮不同的滲透系數(shù)下堆積體的滲流特征,總體表現(xiàn)為：在總的降雨量保持相同的情況下,降雨強(qiáng)度較小,降雨歷時(shí)較長的降雨入滲量更大,入滲深度更深,影響范圍更大；同時(shí)由于在重力作用下,降雨呈現(xiàn)“坡腳匯集作用”,相比較而言,下部的入滲深度,入滲速率較上部大；從不同的滲透系數(shù)來比較,滲透系數(shù)越大其入滲能力越強(qiáng),但非線性比例關(guān)系。 4.庫水位上升的工況下,隨著庫水位按一定速率上升,堆積體前緣被水淹沒,庫水入滲,孔隙水壓力上升,體積含水率增加趨于飽和直至庫水上升至最大蓄水位2254m,地下水位達(dá)到穩(wěn)定。在這一過程中地下水位的抬升相對(duì)于庫水位的上升有明顯的后滯,呈現(xiàn)庫水位上升速率越快、滲透系數(shù)越小,滯后效應(yīng)越明顯的規(guī)律。 5.從穩(wěn)定性變化來看,降雨入滲條件下決定堆積體穩(wěn)定性的是最危險(xiǎn)滑面的強(qiáng)度,三種降雨方案對(duì)孟底溝堆積體(k=k1取滲透性系數(shù)下限時(shí))的穩(wěn)定性系數(shù)在1.51左右?guī)缀鯚o影響,堆積體穩(wěn)定性較好；當(dāng)且僅當(dāng)k=k2取滲透性系數(shù)上限時(shí),降雨強(qiáng)度較小,降雨歷時(shí)的越大的方案才會(huì)降低堆積體穩(wěn)定性,而且表現(xiàn)出降雨歷時(shí)越長,穩(wěn)定性降低幅度越大的特點(diǎn)；對(duì)于庫水位上升過程中,隨著前緣逐漸淹沒,穩(wěn)定性系數(shù)逐漸降低,穩(wěn)定性系數(shù)從1.151降低至1.06左右,直至地下水位穩(wěn)定性,處于極限平衡狀態(tài)。穩(wěn)定性降低的幅度只與庫水位上升的幅度有關(guān),與庫水位上升速率、滲透性系數(shù)無明顯關(guān)系,而穩(wěn)定性系數(shù)開始下降的時(shí)間和下降的速率與水位上升速率和滲透系數(shù)有關(guān),總體表現(xiàn)為庫水位上升速率越快滲透性系數(shù)越大,穩(wěn)定性系數(shù)開始下降的時(shí)間越短,下降的速率也越快。
[Abstract]:The stability of the accumulation body in front of the mongdi gully dam has a vital role and influence on the safety construction and operation of the Mencian hydropower station. Through the detailed geological survey on the site, the engineering geological characteristics of the project area are investigated, the spatial distribution, structural features and geological causes of the accumulation body are analyzed, and the qualitative judgment of the accumulation body in front of the Mondi gully dam is made. Based on the overall understanding, the basic physical and mechanical parameters are obtained by indoor experiments. Due to the engineering characteristics of the pre dam accumulation, the variation of rainfall and reservoir water level is the most important factor for its stability. In this paper, the saturated unsaturated soil theory is used to determine the rising rate of the water level of the monddic gully accumulation under different rainfall schemes. Under the condition of the comprehensive analysis of the seepage field characteristics, the pore water pressure and the change law of the volume water content are obtained. Then the influence of the change of the reservoir water level on the stability of the Mondi gully accumulation body is calculated and analyzed by the limit equilibrium method. This has a guiding role for the construction of the project. It is centered around the permeability characteristics and stability of the accumulation body. This article gets the following understanding:
1. through the investigation and analysis of the geological history, topography and geomorphology, the composition of the particles and the structure characteristics of the accumulation body, it is believed that the accumulation body should be a moraine deposit left over by glacial movement in the last glacial period in the western part of China.
2. through the indoor large shear test, the large triaxial test and the permeability test, the natural and saturated shear strength indexes and the permeability coefficient are obtained, and the suggested values of the strength parameters of the soil sample are put forward.
Under 3. rainfall conditions, through different rainfall schemes and considering the seepage characteristics of the accumulations under different permeability coefficients, the overall performance is that under the same total rainfall, the rainfall intensity is smaller, the rainfall duration is longer, the depth of infiltration is deeper, and the influence range is greater; at the same time, the effect of gravity is greater. In comparison, the infiltration rate in the lower part is larger than that in the upper part, and the greater the permeability coefficient, the stronger the infiltration capacity, but the nonlinear proportional relation.
4. under the condition of rising water level, as the reservoir water level rises at a certain rate, the front edge of the accumulation body is flooded, the reservoir water is infiltrated, the pore water pressure rises, the volume water content increases to saturation until the reservoir water rises to the maximum water level 2254m, and the groundwater level reaches stability. The uplift of the groundwater level in this process is relative to the rise of the reservoir water level. The obvious hysteresis shows that the faster the water level rises, the smaller the permeability coefficient is, the more obvious the hysteresis effect is.
5. from the stability change, the stability of the accumulation body is the most dangerous sliding surface strength under the rainfall infiltration condition. The stability coefficient of the three rainfall schemes has almost no effect on the Mencius gully accumulation (k=k1 permeability coefficient lower limit), and the stability of the accumulation body is better. When and only when the permeability coefficient of the k=k2 is limited, the rainfall is limited. The smaller the intensity, the larger the rainfall duration will reduce the stability of the accumulation body, and show the longer the duration of the rainfall, the greater the stability reduction, the stability coefficient gradually decreases with the front edge drowning, and the stability coefficient decreases from 1.151 to about 1.06, until the groundwater level is stable. The amplitude of stability reduction is only related to the rise of reservoir water level, which has no obvious relation to the rising rate of reservoir water level and permeability coefficient, while the time and the rate of falling stability coefficient are related to the rising rate and permeability coefficient of the water level, and the overall performance is the faster permeability of the rise rate of the reservoir water level. The greater the coefficient, the shorter the time to start the descent of the stability coefficient and the faster the rate of descent.
【學(xué)位授予單位】：成都理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TV223.4

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 何元慶;四川螺髻山地區(qū)某些混雜堆積物的成因探討[J];冰川凍土;1986年04期

2 唐永儀;太白山末次冰期冰磧物微結(jié)構(gòu)和微構(gòu)造研究[J];冰川凍土;1990年03期

3 焦克勤,沈永平;唐古拉山地區(qū)第四紀(jì)冰川作用與冰川特征[J];冰川凍土;2003年01期

4 施雅風(fēng)，李吉均;80年代以來中國冰川學(xué)和第四紀(jì)冰川研究的新進(jìn)展[J];冰川凍土;1994年01期

5 黃培華;黃山山麓第四紀(jì)粘土礫石層形成機(jī)制和環(huán)境的研究[J];地理科學(xué);1994年03期

6 陳正漢,王權(quán)民,李剛,孫樹國;非飽和土的力學(xué)理論[J];重慶大學(xué)學(xué)報(bào)(自然科學(xué)版);2000年S1期

7 黃潤秋,戚國慶;非飽和滲流基質(zhì)吸力對(duì)邊坡穩(wěn)定性的影響[J];工程地質(zhì)學(xué)報(bào);2002年04期

8 嚴(yán)福章,王思敬,徐瑞春;清江隔河巖水庫蓄水后茅坪滑坡的變形機(jī)理及其發(fā)展趨勢(shì)研究[J];工程地質(zhì)學(xué)報(bào);2003年01期

9 張明;胡瑞林;;金沙江下咱日堆積體的成因和穩(wěn)定性初步分析[J];工程地質(zhì)學(xué)報(bào);2008年04期

10 張永雙;曲永新;王獻(xiàn)禮;姚鑫;郭長寶;;中國西南山區(qū)第四紀(jì)冰川堆積物工程地質(zhì)分類探討[J];工程地質(zhì)學(xué)報(bào);2009年05期

，

本文編號(hào)：2109590