【摘要】：在建瀾滄江苗尾水電站位于云南省云龍縣境內(nèi)，擬建壩型初擬為硅面板堆石壩，設(shè)計壩高138m，正常蓄水位1408m，，庫容7.01億m3，總裝機容量120×104KW。壩址區(qū)地質(zhì)環(huán)境復(fù)雜，巖體傾倒變形現(xiàn)象發(fā)育，在施工開挖過程中，出現(xiàn)了一系列的變形現(xiàn)象，傾倒巖體邊坡的穩(wěn)定性對于右壩肩邊坡施工期及運營期意義重大。因此，本文以瀾滄江苗尾水電站右壩肩邊坡為研究對象，采用地質(zhì)分析法、數(shù)值模擬分析法和剛性極限平衡法等，深入分析和研究了右壩肩邊坡開挖后的變形響應(yīng)特征并對其穩(wěn)定性進行了評價。通過較為系統(tǒng)的研究分析，本文主要取得了以下的研究成果和基本認識： （1）根據(jù)前期地質(zhì)勘察資料，結(jié)合施工期地質(zhì)條件的現(xiàn)場調(diào)查和復(fù)核，研究了右壩肩邊坡巖體結(jié)構(gòu)特征，結(jié)果表明：右壩肩邊坡坡腳以軟巖為主，中部及中上部為軟硬巖互層組合，邊坡范圍內(nèi)發(fā)育的結(jié)構(gòu)面主要為Ⅲ2、Ⅲ3、Ⅳ和Ⅴ級結(jié)構(gòu)面。 （2）根據(jù)在現(xiàn)場對壩基巖體以及邊坡傾倒巖體的巖體結(jié)構(gòu)精細描述，分析了邊坡傾倒變形巖體與壩基基巖之間的區(qū)別，優(yōu)勢結(jié)構(gòu)面發(fā)育特征以及對邊坡穩(wěn)定性的控制作用。與此同時，根據(jù)平硐編錄并結(jié)合前期研究成果，建立了右壩肩邊坡傾倒變形強烈程度地質(zhì)模型。 （3）通過對邊坡開挖離散元數(shù)值模擬，分析了邊坡從開挖直至失穩(wěn)的變形發(fā)展過程和開挖引起的不同高程坡體變形響應(yīng)特征，邊坡坡腳部位的開挖造成開口線部位巖體變形，且為其上部巖體提供變形空間，從而導(dǎo)致邊坡傾倒巖體變形持續(xù)發(fā)展，自開口線向邊坡中上部變形逐漸增強，尤其表層巖體受傾坡外結(jié)構(gòu)面的影響，傾倒變形可能轉(zhuǎn)化為滑移-拉裂的變形破壞模式。 （4）通過有限差分FLAC3D數(shù)值模擬分析了邊坡開挖前、開挖后以及現(xiàn)有支護條件下的穩(wěn)定性狀況，結(jié)果表明：原始邊坡的變形主要集中在邊坡A類巖體中，開挖后在坡體內(nèi)部以及中上部坡表出現(xiàn)了拉應(yīng)力集中區(qū)，變形向內(nèi)部發(fā)展，擴展至B1類巖體中部，穩(wěn)定性受到影響；邊坡現(xiàn)有支護基本能抑制由于開挖引起的變形。 （5）采用極限平衡法對邊坡開挖后現(xiàn)有支護條件下進行了不同工況的穩(wěn)定性計算，計算結(jié)果表明：邊坡在現(xiàn)有支護條件下穩(wěn)定性系數(shù)基本滿足相關(guān)規(guī)范要求，但在蓄水+地震的極端工況下，穩(wěn)定性系數(shù)降至1.1以下，處于基本穩(wěn)定狀態(tài)。 （6）從邊坡變形監(jiān)測數(shù)據(jù)分析結(jié)果來看，邊坡前期變形主要出現(xiàn)在坡的中上部，特別是上部變形較大，自上而下逐漸減小，邊坡的坡表變形較大，沿坡體深度遞減較快，自坡表向坡內(nèi)逐漸減小。開口線以上支護實施以后，邊坡變形趨于收斂穩(wěn)定。
[Abstract]:The Miaowei Hydropower Station of Lancang River is located in Yunlong County, Yunnan Province. The proposed dam type is originally designed as a silicon face rockfill dam with a design height of 138m, a normal water level of 1408m, a storage capacity of 701 million m3 and a total installed capacity of 120x104KW. The geological environment of the dam site is complex and the phenomenon of rock mass toppling deformation is developed. During the construction and excavation a series of deformation phenomena occur. The stability of the toppling rock slope is of great significance for the construction and operation period of the right abutment slope. Therefore, the right abutment slope of Miaowei Hydropower Station in Lancang River is taken as the research object. Geological analysis method, numerical simulation analysis method and rigid limit equilibrium method are used in this paper. The deformation response characteristics of right abutment slope after excavation are analyzed and studied and its stability is evaluated. Through systematic research and analysis, this paper has mainly obtained the following research results and basic understanding: (1) according to the data of early geological survey, combined with the field investigation and review of geological conditions during the construction period, The rock mass structure characteristics of the right abutment slope are studied. The results show that the soft rock is dominant in the foot of the slope at the right abutment side, the soft and hard rock interbedded assemblage in the middle and upper part of the slope, and the structural planes of grade 鈪

本文編號：2295980