土建專業(yè)畢業(yè)設(shè)計外文翻譯--孔隙水壓力作用下土坡的極限分析-免費閱讀
【正文】 ()L L L Li i i i ij ij ij ij ijS V V VT v d S X v d V d V p d V? ? ? ? ??? ? ? ?? ? ? ? ()ij ij ijVVD d V d V? ? ????? (5) 這里 Lij? 是不包括滲透量和浮力的自重與摩擦力平衡時的靜態(tài)允許應(yīng)力。Aij? 是在 AiT和 AijX 平衡下的有效應(yīng)力張量；ij?是 Kronecker 增量； P 是孔隙水壓力；Bij? 是與速度場 Biv 一致的應(yīng)變率張量。39。為了模仿應(yīng)力場和速度場，由三點組成的三邊線性元素就要被利用?？紫端畨毫Ρ豢紤]用孔隙水壓力比來表示： /ur u z?? 這里， u 是孔隙水壓力； ? 是沙土的比重； z 是土體表面以下的深度。在極限平衡法中，孔隙水壓力是通過限定一個地下水表面和一個可能的流動網(wǎng)或者通過一個孔隙水壓力比率模擬地下水條件推測出來的。極限分析法在以下兩種意義上是嚴密的，一是土體在外加荷載作用下的平衡，下邊界解所對應(yīng)的應(yīng)力場；二是與外加位移相協(xié)調(diào)，上邊界所對應(yīng)的速度場。 求 解 通常 建立在 滑移 線 方法 上 ，極限平衡方法或極限分析法的基礎(chǔ)上。通過解決由平衡協(xié)調(diào)條件以及沙土的本構(gòu)關(guān)系推出的微分方程，從而得到邊界條件下的解。極限分析法充分利用了塑性體的上下邊界原理，在求真實解中提供了一個相對簡單但又嚴密的邊界。 and Bij? = strain rate tensor patible with the velocity field Biv . There is no need for Aij? , AiT , and AijX? to be related to Bij? and Biv in any particular way for (3) or (4) represent the rate of the external work, while the righthand sides represent the rate of the internal power dissipation done by the assumed stress field and external loads on the assumed strain and velocity fields. The difference between (3) and (4) is the way to incorporate the effect of porewater pressure: the porewater pressures are considered as internal force, reducing the internal power dissipation, in (3), while they are considered external force in (4). By taking advantage of the normality condition , it can be easily shown that elastic stress and strain have no influence on the collapse load。A B A B Bi i i i ij ijS V VT v dS X v dV dV????? ? ? （ 4） Where AiT = boundary loadings。 and (2) to check the accuracy of Bishop’s simplified method for slope stability analysis by paring Bishop’s solution with lowerand upperbound solution. The present study is an extension of previous research, where Bishop’s simplified limitequilibrium solutions are pared with lowerand upperbund solutions for simple slopes without considering the effect of porewater pressure. In the present paper, the effect of porewater pressure is considered in both lowerand upperbound limit analysis under planestrain conditions. Porewater pressures are accounted for by making modifications to the numerical algorithm for lowerand upperbound calculations using linear threenoded triangles developed by Sloan and Sloan and Kleeman. To model the stress field criterion, flow of linear equations in terms of nodal stresses and porewater pressures, or velocities, the problem of finding optimum lower and upperbound solutions can be set up as a linear programming problem. Lower and upperbound collapse loadings are calculated for several simple slope configurations and groundwater patterns, and the solutions are presented in the form of chart. LIMIT ANALYSIS WITH POREWATER PRESSURE Assumptions and Their implementation Limit analysis uses an idealized yield criterion and stressstrain relation: soil is assumed to follow perfect plasticity with an associated flow rule. The assumption of perfect plasticity expresses the possible states of stress in the form F( 39。ij? ) = 0 (1) Where F( 39。 AijX? = body forces not including seepage and buoyancy forces。 that is, only plastic deformation occurs during plastic flow, and ij? = Pij? .This makes limit analysis a simple method to solve stability problems, without loss of rigor, assuming rigid perfect plasticity.
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