本文關(guān)鍵詞： 岸坡穩(wěn)定 極限平衡法 耦合分析 滲流場 應(yīng)力場　出處：《暨南大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：庫岸滑坡問題是水庫蓄水誘發(fā)的災(zāi)害之一,隨著大型水利工程的興建,岸坡險(xiǎn)情分布范圍擴(kuò)大,岸坡在水位變動下的穩(wěn)定問題越來越受到學(xué)術(shù)界和工程界關(guān)注。目前,許多岸坡的研究工作中,滲流分析和應(yīng)力分析是分開單獨(dú)計(jì)算的,但是只要有水的地方,應(yīng)力場和滲流場就會相互影響、相互作用,處于一種復(fù)雜的動態(tài)變化過程中,構(gòu)成了流固耦合關(guān)系。本文在總結(jié)前人研究成果的基礎(chǔ)上,基于極限平衡理論和滲流場-應(yīng)力場耦合理論對一水庫近壩區(qū)的一實(shí)際古滑坡進(jìn)行了穩(wěn)定性分析。首先采用極限平衡法進(jìn)行穩(wěn)定分析,然后基于滲流場-應(yīng)力場耦合理論建立數(shù)學(xué)模型并求得其有限元解,通過對各種工況下的岸坡穩(wěn)定進(jìn)行基于耦合理論的數(shù)值分析,研究水位變動下岸坡的穩(wěn)定狀態(tài),并根據(jù)分析結(jié)果提出了加固方案。計(jì)算結(jié)果表明,加固后的邊坡可以應(yīng)對各種設(shè)計(jì)工況,滿足穩(wěn)定要求。論文主要研究內(nèi)容與成果如下:(1)水庫第一次蓄水條件下岸坡穩(wěn)定性預(yù)測。水庫蓄水會提高滑坡體內(nèi)的地下水位,改變原有的滲流場,隨著滲流區(qū)域增大,沿滲流方向的動水壓力將增大岸坡的下滑力,又因?yàn)榘镀缕履_被淹沒,水下土體抗剪強(qiáng)度衰減,岸坡的抗滑力將被削減,使得岸坡前緣存在滑動危險(xiǎn)。本文分析結(jié)果顯示,岸坡前緣在水位上升過程中產(chǎn)生了趨向水庫方向的較大位移,形成明顯的滑動區(qū)域,坡體前緣局部失穩(wěn)。邊坡整體安全系數(shù)也隨水位上升明顯下降到低于規(guī)范要求。根據(jù)計(jì)算結(jié)果,可知岸坡在水庫第一次蓄水過程中將處于不穩(wěn)定狀態(tài)。(2)坡腳滑動對岸坡穩(wěn)定性的影響分析。分析表明,水位上升導(dǎo)致坡腳局部滑動后,岸坡原來的平衡狀態(tài)被打破,應(yīng)力場將重新分布,坡體中上部因失去坡腳土體的支撐可能沿著古滑動帶產(chǎn)生下滑,存在復(fù)活的危險(xiǎn)。本文分析結(jié)果揭示了水位上升過程中岸坡中部、下部古滑動帶處剪切變形區(qū)域擴(kuò)大,貫通坡腳,坡體有沿著古滑動帶向水庫方向滑動的趨勢,岸坡整體安全系數(shù)因前緣坡腳失穩(wěn)從1.759降至0.992。由此可知,若岸坡前緣失穩(wěn),中上部坡體失去支撐而沿古滑動帶整體下滑,將形成牽引式滑坡。(3)坡腳加固對岸坡穩(wěn)定性的作用。為防止岸坡牽引式滑坡的形成,本文建立了對岸坡坡腳進(jìn)行壓重加固的數(shù)值分析模型,計(jì)算結(jié)果表明,無論是水庫蓄水還是水位驟降,岸坡的位移量都明顯減少,坡腳沒有形成滑動區(qū)域,也沒有局部滑動的趨勢。雖然滑坡體沿古滑動帶有局部、少量的剪切變形帶,但對于坡體整體穩(wěn)定、坡體前緣局部穩(wěn)定都沒有造成明顯的不良影響。由此可知,坡腳加固的措施能夠有效地增強(qiáng)坡腳材料的抗剪強(qiáng)度,提升坡腳抗滑力,從而遏制牽引式滑坡機(jī)制的形成,加固后岸坡處于穩(wěn)定狀態(tài)。(4)基于變形監(jiān)測的邊坡預(yù)警系統(tǒng)研究。由于實(shí)測元件方面的制約,目前邊坡監(jiān)測的內(nèi)容一般是針對監(jiān)測點(diǎn)位移,很少有針對材料強(qiáng)度進(jìn)行的監(jiān)測,但是邊坡穩(wěn)定性的判別模型和方法一般是基于材料的強(qiáng)度,這就存在一個明顯的不銜接。針對這一現(xiàn)狀,本文從簡單適用的原則出發(fā),以現(xiàn)行規(guī)范推薦的極限平衡法為基礎(chǔ),初步建立了考慮強(qiáng)度-應(yīng)變軟化關(guān)系的邊坡穩(wěn)定預(yù)警系統(tǒng)。然后以一簡單邊坡為例給出了基于變形監(jiān)測資料的穩(wěn)定預(yù)警流程。在此基礎(chǔ)上,本文進(jìn)一步結(jié)合有限元技術(shù)對此預(yù)警系統(tǒng)的平臺進(jìn)行了擴(kuò)充,使之可容納更多如流固耦合的巖土專業(yè)研究成果,有望形成基于變形監(jiān)測和強(qiáng)度-應(yīng)變軟化理論的預(yù)警系統(tǒng),以便更適用于水庫管理和邊坡滑動防治。
[Abstract]:Landslide is one of the disasters induced by reservoir impounding, with large-scale water conservancy engineering, the distribution range of the slope stability problem of slope in danger of expansion, water level changes under more and more attention in academia and engineering. At present, many research works of slope, seepage flow analysis and stress analysis are calculated separately however, as long as there is water, stress field and seepage field will influence each other, interaction is a complex dynamic process, a coupling relation. Based on the summary of previous research results, the limit equilibrium theory and the seepage field and stress field coupling theory of a reservoir near the actual landslide stability is analyzed firstly. Based on the limit equilibrium method for stability analysis, and then based on the seepage and stress field coupling theory to establish the mathematical model and calculate its finite element solution, This paper makes a numerical analysis based on the coupling theory of the slope stability under various conditions, the research of water level change of stable state of slope, and the reinforcement program is put forward according to the analysis results. The calculation results show that the slope after reinforcement can deal with all kinds of design condition, meet the stability requirements. The main research contents and results are as follows: (1) reservoir the first impoundment conditions. The slope stability prediction of reservoir will increase the groundwater level of the landslide, the change of seepage field of the original, with the seepage area increases, the sliding force along the flow direction of the hydrodynamic pressure will increase the slope, and slope toe because flooded, the shear strength of soil under water attenuation, sliding force will be anti cut slope, the slope leading edge. In this paper, the existence of sliding risk analysis results show that the larger displacement tends to the direction of the reservoir during the rise in water level in front of slope, the formation of Ming Dynasty The slide area significantly, the leading edge of the slope of local instability. The safety factor of the whole slope also increased significantly with the water level drops below the specification. According to the calculation results, the slope in the reservoir during the first impoundment in an unstable state. (2) analysis of influence on slope sliding slope. Analysis shows that the water level rising slope local sliding, slope breaks the equilibrium state, the stress field will redistribute, the upper slope due to loss of slope soil may support along the ancient sliding zone have declined, there raised the danger. The results revealed that the central bank water level rise, the lower sliding zone ancient shear deformation zone expands through the foot of the slope, the slope along the sliding direction of the reservoir to the ancient sliding trend, the overall safety factor of slope instability due to the front foot from 1.759 to 0.992. so that, if the front of slope In the upper part of the slope instability, loss of support along the ancient sliding zone overall decline, will form a retrogressive landslide. (3) to reinforce the slope stability of the slope. In order to prevent the slope of retrogressive landslide formation, the numerical analysis model is established in this paper. On the other side slope toe pressure heavy reinforcement, the calculation results show that both the the reservoir water level falls or, the displacement of slope are significantly reduced, the slope has not formed sliding region, no local sliding trend. Although the landslide along the ancient slide with local small, shear deformation zone, but for the overall stability of the slope, slope local stability did not cause significant adverse effects from this. The slope reinforcement measures, can effectively enhance the shear strength of slope material, enhance slope anti slide force, in order to prevent the formation of the traction type landslide mechanism, the slope is in a stable state after reinforcement. (4) based on deformation Study on slope monitoring early warning system. Due to the restriction of actual components, the slope monitoring content is general for displacement monitoring points for monitoring of material strength is little, but the slope stability model and method is generally based on the strength of the material, there is not a clear convergence. In view of this situation this paper, from the simple application of the principle of limit equilibrium method to the current standard recommended as the foundation, established the early warning system of slope stability considering the strength and strain softening relationship. Then a simple slope for example gives the stability of deformation monitoring data based on the early warning process. On this basis, this paper further combined with the finite element technique this early warning system platform is extended, which can accommodate more fluid solid coupling of geotechnical professional research, is expected to form based on the deformation monitoring and intensity should be The early warning system of the theory of variable softening is more suitable for the management of reservoir and the prevention and control of slope sliding.

【學(xué)位授予單位】：暨南大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TV223

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