码头桩基与岸坡相互作用的数值模拟

本文以华南某码头为工程实例，针对桩基码头的工程问题，通过现场观测、离心模型试验、砂槽模型试验和有限元数值模拟分析，着重研究由堆场填土和地面荷载引起的岸坡变形及其对码头桩基的影响，并提出相应的码头桩基-岸坡稳定分析和桩基性状的简化计算方法。 首先根据Mohr-Coulomb屈服准则推导了半无限土坡在坡项竖向荷载作用下的应力计算公式。研究表明，在坡顶荷载q作用下，半无限土坡将经历弹性—弹塑性的变化过程。当q小于临塑荷载qp时，土坡处于弹性状态，当q=qp时，土坡处于临塑状态，从临塑角处开始出现塑性变形。随着q的继续增大，塑性区不断扩大，土坡处于弹塑性状态，当q等于极限荷载qf时，土坡达到极限平衡状态，坡内应力可分为三个区。文中还给出了半无限土坡临塑角θp、临塑荷载系数Np和弹塑性状态的θ1值的计算图表。 桩基码头中，岸坡变形的影响几乎是无法避免的。为此，趁湛江港某码头一期工程修复之际，在结构和岸坡中埋设和安装了钢筋计、反力计和测斜管，以测定6#斜桩的受力、后方承台对前方承台的水平推力、深层土体的水平位移。观测结果发现，6#桩的轴向拉力还有增长的趋势，桩顶受到了一个朝海方向弯矩的作用，水平推力虽然不大，但一直在增长，深层土体几乎没有水平位移。这些结果表明，在码头竣工初期，以侧向变形为主，引起码头向前位移。经过4～5年后，其影响可能逐渐衰减，而岸坡中不均匀沉降的影响可能慢慢上升为控制因素。
逆变焊机
A pile-supported pier in south China is taken as an engineering example. Field observation, centrifuge model test, laboratory model test and numerical analysis are carried out according to the engineering problems encountered in the pile-supported pier. The deformation of the bank slope caused by the backfill and surcharge on the top of the slope and its influence on the pile-supported pier are studied in this paper. Simplified methods to analyze the pile — slope stability and pile behaviour are presented.First of all, according to the Mohr-Coulomb yield criterion, the stresses of semi-infinite slope are derived under a vertical uniform load q on the top of the slope. It is indicated that elastic and elasto-plastic states would occur in the slope. When q is less than the critical load, qp, the slope is in elastic state. If q equals qp, the slope is in critical state, and the plastic deformation may occur beyond the critical angle, θp. With the increase of q, the plastic zone would extend, and the slope is in the elasto-plastic state. If q equals limit load, qf, the slope is in limit equilibrium state. The slope may be divided into three zones. Some charts of θp, the critical load coefficient and the elasto-plastic stress angle are presented in this paper.The influence of deformation of slope on the pile-supported pier is almost unavoidable. During the repairing process of a damaged pile-supported pier, strain gauges, manometers and inclinometer tubes were installed in the structure of this pier and in the bank slope, in order to measure the axial force of battered pile 6#, the lateral thrusts transmitted from the rear platform to the frontal platform and the displacement of bank slope. The tensile forces of piles 6# were increasing, and there