【摘要】：砂土液化是地震中一種常見的土體破壞形式,其造成的土體大變形和巨大的上浮壓力是埋地管線系統(tǒng)最危險的破壞因素。因此,研究埋地管線抵御砂土液化設(shè)計(jì)理論和方法是確保其在液化場地中的安全至關(guān)重要一環(huán)�；谝夯瘯r巨大的砂土上浮力和液化后土體沉降兩種最常見的現(xiàn)象,本文探究了連續(xù)管線和帶有橡膠圈柔性接頭的非連續(xù)管線在這兩種工況下的形變特征,為合理設(shè)計(jì)埋地管線的抗液化措施提供可靠指導(dǎo)。本文的主要工作和研究結(jié)果概況如下:1.基于ANSYS平臺,建立非液化土體與管線的非線性接觸模型、液化區(qū)土體與管線間的土體彈簧模型,系統(tǒng)分析了連續(xù)管線和非連續(xù)管線在液化土體中的應(yīng)力分布和形變特征。結(jié)果表明,考慮管線與土體相互作用時,液化區(qū)的土彈簧模型和非液化的非線性接觸模型能合理模擬管土相互作用規(guī)律。2.建立了連續(xù)管線和帶有橡膠圈柔性接頭的非連續(xù)管線在液化場地下的上浮模型,考慮土體和管材的材料非線性以及管線發(fā)生大變形時的幾何非線性,用殼體單元模擬管線,彈簧單元模擬橡膠圈柔性接頭。結(jié)果顯示,連續(xù)管線最危險的位置為液化與非液化土體的相交處以及液化區(qū)中間位置,液化區(qū)范圍是影響連續(xù)管線上浮的關(guān)鍵因素,因而可以通過控制連續(xù)管線在液化區(qū)中的間隔防止管線破壞;非連續(xù)管線的上浮位移比連續(xù)管線大得多,應(yīng)力主要集中在接頭位置附近,上浮位移、接頭最大轉(zhuǎn)角以及接頭最大拔出長度會隨著液化區(qū)接頭數(shù)量的增多而增大。3.建立了連續(xù)管線和非連續(xù)管線在液化后土體沉降的分析模型。比較不同土質(zhì)下連續(xù)管線和非連續(xù)管線的反應(yīng),發(fā)現(xiàn)非液化土體剛度較小時,非連續(xù)管線通過接頭的轉(zhuǎn)動可以吸收較大的液化沉降位移而不發(fā)生破壞。非液化土體剛度較大時,非連續(xù)管線較連續(xù)管線更容易發(fā)生管體壓縮破壞,減小沉降交界處管段長度是防止管體破壞的有效措施。
[Abstract]:Sand liquefaction is a common form of soil failure in earthquake. The large deformation of soil and the huge floating pressure are the most dangerous failure factors in buried pipeline system. Therefore, it is very important to study the theory and method of sand liquefaction design for buried pipeline in order to ensure its safety in liquefaction site. Based on the two most common phenomena during liquefaction, the buoyancy of sand and the settlement of soil after liquefaction, the deformation characteristics of continuous pipeline and discontinuous pipeline with flexible joint of rubber ring under these two conditions are investigated in this paper. It provides reliable guidance for rational design of anti-liquefaction measures of buried pipeline. The main work and results of this paper are summarized as follows: 1. Based on the ANSYS platform, the nonlinear contact model between non-liquefaction soil and pipeline, and the soil spring model between liquefaction soil and pipeline are established. The stress distribution and deformation characteristics of continuous pipeline and discontinuous pipeline in liquefaction soil are analyzed systematically. The results show that the soil-spring model and the non-liquefaction nonlinear contact model can reasonably simulate the pipe-soil interaction law when the interaction between pipeline and soil is considered. The floating model of continuous pipeline and discontinuous pipeline with rubber ring flexible joint in liquefaction field is established. Considering the material nonlinearity of soil and pipe and the geometric nonlinearity of pipeline in large deformation, the pipeline is simulated by shell element. Spring element simulates rubber ring flexible joint. The results show that the most dangerous position of continuous pipeline is the intersection of liquefaction and non-liquefaction soil and the middle position of liquefaction zone. The range of liquefaction zone is the key factor affecting the floating of continuous pipeline. Therefore, the failure of the pipeline can be prevented by controlling the spacing of the continuous pipeline in the liquefaction zone. The floating displacement of the discontinuous pipeline is much larger than that of the continuous pipeline, and the stress is mainly concentrated near the joint position. The maximum angle and the maximum pull-out length of the joint will increase with the increase of the number of joints in the liquefaction zone. An analytical model of soil settlement after liquefaction of continuous pipeline and discontinuous pipeline is established. By comparing the reaction of continuous pipeline and discontinuous pipeline under different soil quality, it is found that when the stiffness of non-liquefaction soil is relatively small, the discontinuous pipeline can absorb larger liquefaction settlement displacement without destruction through the rotation of joint. When the stiffness of non-liquefaction soil is large discontinuous pipeline is more prone to pipe compression failure than continuous pipeline. Reducing the length of pipe section at the settlement junction is an effective measure to prevent pipe body damage.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TU435;TU990.3

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本文編號：2292785