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  本文選題：止水帷幕 + 土釘墻�。� 參考：《河北工程大學》2017年碩士論文

【摘要】：在現(xiàn)行規(guī)范與工程設計中,止水帷幕一般當作安全儲備而不考慮其擋土作用,往往使基坑支護設計偏于保守,容易造成工程浪費,不利于土釘墻支護技術的推廣。因此研究止水帷幕對土釘墻工作性能的影響很有必要。本文針對水泥土樁止水帷幕+土釘支護這種復合土釘墻支護形式,利用顯示有限差分軟件FLAC 3D以摩爾-庫倫本構模型、強度折減法、傳統(tǒng)極限平衡法等理論為基礎,結合某基坑工程案例按照具體施工工況建立了考慮止水帷幕與不考慮止水帷幕的兩種計算模型。通過對計算結果的對比,定量分析了止水帷幕對土釘墻的增強程度。為了驗證數(shù)值模擬的可靠性,還和現(xiàn)場實際監(jiān)測數(shù)據(jù)進行了比對。文中從土釘墻的整體穩(wěn)定性、變形與土釘軸力三個方面,總結了止水帷幕對土釘墻增強幅度的量化指標。(1)止水帷幕增加了塑性區(qū)的范圍,被動土區(qū)域塑性區(qū)范圍的增加最為明顯,說明了被動土作用范圍在擴大;止水帷幕還有效阻隔了邊坡塑性區(qū)的貫通,塑性貫通區(qū)繞過了止水帷幕的底部向外擴展,相應的滑裂面范圍向外擴展較明顯;考慮止水帷幕土釘墻支護的安全系數(shù)最大可提高近30%。(2)止水帷幕減小了土釘墻坡頂44%的沉降,沉降較大區(qū)域整體向遠離基坑的方向移動,最大沉降點遠離到了1.42倍基坑深度外,優(yōu)化幅度較大;止水帷幕減小了土釘墻坡面49.6%的水平位移,水平位移較大區(qū)域的范圍也有所縮小,被動土壓力區(qū)產(chǎn)生作用的區(qū)域有所擴大;施工過程中土釘墻的垂直位移與水平位移均逐漸增加且整體變化幅度相對比較均勻,位移趨勢基本一致,說明了止水帷幕在一定程度上有效抑制了土釘墻的變形。(3)在考慮止水帷幕作用時土釘軸力最大減小幅度為71.9%,在土釘墻的中下部減小幅度最為明顯。研究表明,止水帷幕對土釘墻的增強作用相當明顯,考慮其作用可以進一步優(yōu)化基坑設計,降低工程成本,提高土釘墻支護的性價比。從而使基坑設計更加貼合工程實際,有利于推廣土釘墻支護技術。
[Abstract]:In the current code and engineering design, the waterproof curtain is generally regarded as a safe reserve without considering its retaining effect, which often causes the foundation pit support design to be conservative, which is easy to cause engineering waste, and is not conducive to the popularization of soil nailing wall supporting technology. Therefore, it is necessary to study the influence of waterproof curtain on the working performance of soil nailing wall. In this paper, in view of the composite soil nailing wall support form of cement soil pile waterproof curtain and soil nailing, the display finite difference software FLAC 3D is based on the theory of Moore Coulomb constitutive model, strength reduction method, traditional limit equilibrium method, and so on. Combined with a foundation pit engineering case, two calculation models are established according to the concrete construction conditions, which consider the waterproof curtain and do not consider the waterproof curtain. Through the comparison of the calculation results, the reinforcement degree of the waterproof curtain to the soil nailing wall is quantitatively analyzed. In order to verify the reliability of the numerical simulation, the field monitoring data are compared. In this paper, from the aspects of overall stability, deformation and axial force of soil nailing wall, the paper summarizes the quantitative index. The increase of the plastic zone in the passive soil area is the most obvious, which indicates that the action range of the passive soil is expanding, and the water-stop curtain also effectively obstructs the penetration of the plastic zone of the slope, and the plastic penetrating zone bypasses the bottom of the waterproof curtain and extends outwards. The corresponding range of sliding crack surface extends outward obviously, considering that the maximum safety factor of water-stop curtain soil nailing wall support can be increased by nearly 30%.) the waterproof curtain reduces the settlement of the slope top of soil nailing wall by 44%, and the settlement of the larger area moves away from the foundation pit as a whole. The maximum settlement point is far from the depth of 1.42 times of foundation pit, and the optimization range is larger, the horizontal displacement of soil nailing wall slope is reduced by 49.6%, and the range of horizontal displacement area is also reduced. In the process of construction, the vertical displacement and horizontal displacement of the soil nailing wall increase gradually, the whole variation range is relatively uniform, and the displacement trend is basically the same. The results show that the deformation of soil nailing wall can be effectively restrained by the waterproof curtain to a certain extent) the maximum reduction range of axial force of soil nailing is 71.9 when considering the action of water-proof curtain, and the most obvious decrease is in the middle and lower part of soil nailing wall. The research shows that the reinforcement effect of the waterproof curtain on the soil nailing wall is quite obvious. Considering its effect, the foundation pit design can be further optimized, the engineering cost can be reduced, and the performance and price ratio of the soil nailing wall support can be improved. Therefore, the foundation pit design is more suitable for engineering practice and is conducive to popularizing soil nailing wall support technology.
【學位授予單位】：河北工程大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TU753

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本文編號：1844049