本文選題：折線滑動(dòng)模式　切入點(diǎn)：堆積層滑坡　出處：《湘潭大學(xué)》2017年碩士論文

【摘要】：堆積層滑坡是滑坡地質(zhì)災(zāi)害中分布最為廣泛的一類,折線滑動(dòng)是其一種基本的滑移失穩(wěn)形式。在折線滑面滑坡的穩(wěn)定性分析和治理研究方法中應(yīng)用最為廣泛的是我國(guó)獨(dú)創(chuàng)的不平衡推力法(ITFM)。該法不僅考慮了土條界面上剪力的影響,還可以獲得任意形狀滑動(dòng)面在復(fù)雜荷載作用下的滑坡推力數(shù)值,計(jì)算簡(jiǎn)潔,適用于任意形狀的滑裂面,不需要經(jīng)過(guò)迭代計(jì)算而給出能夠滿足一般工程需要的穩(wěn)定系數(shù)值,并且能夠?yàn)榛轮卫硖峁┰O(shè)計(jì)推力值。但此法不足之處是只適用于已經(jīng)完全滑動(dòng)的邊坡,且在滑塊傾角變化過(guò)大時(shí)使穩(wěn)定系數(shù)計(jì)算結(jié)果偏大、滑坡推力值偏小。因此,為了研究正處于發(fā)展變形中的滑坡在折線滑動(dòng)模式下的穩(wěn)定性規(guī)律,本文依據(jù)極限平衡法和有限元強(qiáng)度折減法(SRFEM)基本理論,以新晃縣某滑坡工程實(shí)例為研究對(duì)象,分析邊坡在不同工況下的穩(wěn)定性情況以及應(yīng)力—應(yīng)變規(guī)律。主要研究成果如下:(1)改進(jìn)了不平衡推力法的取值方法,該法同時(shí)考慮邊坡巖土體峰值強(qiáng)度和殘余抗剪強(qiáng)度指標(biāo),其值由滑塊的穩(wěn)定狀態(tài)決定,而非定值。當(dāng)Fi(29)1取值ic、i?(土體峰值抗剪強(qiáng)度);Fi(27)1時(shí),為cic、ci?(土體殘余抗剪強(qiáng)度)。(2)根據(jù)現(xiàn)場(chǎng)勘察資料,綜合判定新晃縣某滑坡的失穩(wěn)模式為中型牽引式順層滑坡;分析了滑坡形成機(jī)理,認(rèn)為大氣強(qiáng)降水則是誘因,地形條件(處于溝谷岸坡)和土層條件(土質(zhì)松散、基巖面破碎)是滑坡形成的內(nèi)因,人類工程活動(dòng)對(duì)植被的破壞和坡腳開(kāi)挖則是外因。(3)應(yīng)用ABAQUS軟件模擬了滑坡在自重工況下的整個(gè)失穩(wěn)過(guò)程,計(jì)算得到的塑性區(qū)形態(tài)與現(xiàn)場(chǎng)實(shí)測(cè)滑動(dòng)面基本一致,判定滑動(dòng)面位置為巖土交界面(強(qiáng)風(fēng)化巖與中風(fēng)化巖界面),并以此建立了不平衡推力法計(jì)算模型。(4)采用兩種取值方法分別計(jì)算了自重和暴雨工況下Ⅱ號(hào)滑坡穩(wěn)定系數(shù)和滑坡推力數(shù)值,發(fā)現(xiàn):傳統(tǒng)取值法在分別取值為峰值強(qiáng)度與殘余強(qiáng)度時(shí),計(jì)算結(jié)果相差很大,約為28.6%~43.4%;但后者與改進(jìn)法計(jì)算結(jié)果較為接近,差值約為2.58%~17.5%;改進(jìn)取值法,考慮了邊坡在變形破壞過(guò)程中巖土體強(qiáng)度衰減,原理與強(qiáng)度折減法相近,計(jì)算結(jié)果相較傳統(tǒng)方法更為可靠,接近工程實(shí)際。(5)根據(jù)改進(jìn)取值法所得滑坡推力設(shè)計(jì)的抗滑樁鋼筋消耗相比傳統(tǒng)取值方法可減少約11.5%;提出了預(yù)應(yīng)力錨索抗滑樁+錨桿框格梁的滑坡治理方案,可有效阻斷滑坡塑性區(qū)的發(fā)展和控制坡體變形,處治后的Fs(28)1.76,符合規(guī)范要求。
[Abstract]:The accumulation layer landslide is the most widely distributed type of landslide geological hazard. Broken line sliding is one of the basic slip instability forms. The most widely used method for stability analysis and treatment of broken slip surface landslide is the unbalanced thrust method (ITFMN), which has been created in China. This method not only takes into account the influence of shear force on the interface of soil strip, but also the effect of shear force on the interface of soil strip. The landslide thrust value of any shape sliding surface under complex load can also be obtained. The calculation is simple and suitable for any shape slide crack surface. The stability coefficient value which can satisfy the general engineering needs can be obtained without iterative calculation. And it can provide the design thrust value for landslide treatment. However, this method is only suitable for the slope which has been completely sliding, and when the slope angle of the slide block is too large, the calculation result of the stability factor is too large and the thrust value of the landslide is too small. In order to study the stability law of landslide in developing deformation under the broken line sliding mode, based on the basic theory of limit equilibrium method and finite element strength reduction method (SRFEMM), this paper takes a landslide engineering example in Xinhuang County as the research object. The stability and stress-strain law of slope under different working conditions are analyzed. The main research results are as follows: (1) the unbalance thrust method is improved, which takes into account both peak strength and residual shear strength index of slope and soil mass. The value is determined by the stable state of the slider, not by the fixed value. (peak shear strength of soil is Ciccic? (residual shear strength of soil mass) according to the field investigation data, the instability model of a landslide in Xinhuang County is determined to be a medium type towed bedding landslide, and the formation mechanism of landslide is analyzed, and it is considered that heavy atmospheric precipitation is the inducement. The landform condition (at the gully bank slope) and the soil layer condition (the soil quality is loose, the bedrock surface is broken) are the internal causes of the landslide, The damage of vegetation caused by human engineering activities and excavation of slope foot are external factors. (3) the whole instability process of landslide under deadweight condition is simulated by using ABAQUS software. The calculated plastic zone shape is basically consistent with the field measured sliding surface. The position of sliding surface is determined to be the interface between rock and soil (strong weathered rock and medium weathered rock interface). Based on this, the calculation model of unbalanced thrust method is established. Two methods are used to calculate the stability of landslide 鈪，

本文編號(hào)：1675185