本文選題：斜坡堤 + 應力��； 參考：《大連理工大學》2014年碩士論文

【摘要】：斜坡式防波堤是近海沿岸工程中常用的防浪結構物,其護面層既要起到消浪的效果,又要保持自身的穩(wěn)定。然而在極端海況下,護面層易發(fā)生水力失穩(wěn)和由于塊體斷裂破壞而引起的結構失穩(wěn)。目前關于斜坡堤穩(wěn)定性的研究工作多基于物模試驗,由于比尺效應影響,物模試驗結果往往不能正確反映原型結構的強度。因此以原型尺度開展波浪作用下斜坡式防波堤護面塊體強度破壞的數值模擬研究工作具有十分重要的學術意義和工程應用價值。 本文基于FEM/DEM方法建立二維原型尺度數值模型,模擬波浪荷載作用下斜坡上護面塊體內部的應力分布和斷裂破壞過程。其中結構物的水動力荷載采用微幅波理論模擬,塊體的運動和變形采用FEM/DEM方法模擬。采用基于勢函數的罰函數法計算分布式接觸力,混凝土塊體開裂采用Single/Smeared破壞模型模擬,并采用中心差分法的顯式積分算法進行數值求解計算。模擬了塊體的自重應力分布和塊體碰撞破壞的兩種類型,驗證了數值模型應力和變形的計算精度。通過數值模擬給出了不同波浪荷載下斜坡上護面塊體的運動特性、內部應力分布、裂縫形成和斷裂破壞過程,并給出了不同點的應力歷時曲線,分析了不同波浪荷載作用下塊體內部應力變化規(guī)律,討論了極端海況作用下塊體的運動變化趨勢和斷裂破壞特性。 在二維模型的基礎上,基于3D FEMDEM方法建立三維原型尺度數值模型,模擬波浪荷載作用下斜坡上護面塊體內部的應力分布。有限元計算采用高精度的有限應變有限旋轉的二次四面體單元。比較分析了三維數值模型與ANSYS模型對自重作用下混凝土扭王字塊的內部應力分布,并模擬了塊體下落碰撞過程的動應力變化,驗證了三維數值模型的應力計算精度。應用所建立的數值模型對線性波作用下斜坡上規(guī)則擺放的護面塊體內部的應力分布及其變化特性進行了模擬分析,給出了不同點的應力歷時曲線,并給出不同時刻的應力分布圖和塊體運動趨勢圖,深討了塊體內部應力的變化特性。 數值模擬結果表明：波浪作用下,塊體之間相互碰撞,接觸點應力最大,其次為塊體肢體的連接部分,塊體表面各點應力成周期性變化。扭王字塊整體穩(wěn)定性較好,不易發(fā)生局部失穩(wěn)或整體失穩(wěn),單個塊體的運動趨勢多以平移和翻滾為主。而在極端海況下,個別混凝土塊體可能在兩個肢體的連接部位發(fā)生斷裂破壞,工程上應做加強處理。本論文的研究工作將為防波堤護面塊體的設計提供參考依據。
[Abstract]:Slope breakwater is a commonly used anti-wave structure in offshore coastal engineering. Its protective layer not only has the effect of wave elimination, but also maintains its own stability. However, under extreme sea conditions, hydraulic instability and structural instability caused by block fracture are easy to occur. At present, the research work on stability of slope embankment is mostly based on physical model test. Because of the influence of scale effect, the results of physical model test often can not reflect the strength of prototype structure correctly. Therefore, it is of great academic significance and engineering value to simulate the strength failure of slope breakwater block with the prototype scale. Based on the FEM-Dem method, a 2-D prototype numerical model is established to simulate the stress distribution and fracture failure process of the slope surface block under wave loads. The hydrodynamic loads of structures are simulated by micro-wave theory, and the motion and deformation of blocks are simulated by FEM-Dem method. The penalty function method based on potential function is used to calculate the distributed contact force, and the single / Smeared failure model is used to simulate the crack of concrete block, and the explicit integral algorithm of the central difference method is used to solve the problem numerically. The distribution of gravity stress and the two types of block collision failure are simulated, and the calculation accuracy of the numerical model is verified. Through numerical simulation, the motion characteristics, internal stress distribution, crack formation and fracture failure process of the protection block on the slope under different wave loads are given, and the stress duration curves at different points are given. The variation law of internal stress in blocks under different wave loads is analyzed, and the variation trend of block motion and fracture failure characteristics under extreme sea conditions are discussed. On the basis of two-dimensional model, a three-dimensional prototype numerical model was established based on 3D FEMDEM method to simulate the stress distribution of the block on the slope under wave loads. High precision finite strain finite rotation quadratic tetrahedron element is used in finite element analysis. In this paper, the internal stress distribution of the concrete wrist-wangzhuang block under the self-gravity action of the three-dimensional numerical model and the ANSYS model is compared and analyzed, and the dynamic stress changes during the falling collision of the block are simulated, and the accuracy of the three-dimensional numerical model is verified. The numerical model is used to simulate and analyze the stress distribution and its variation characteristics of the regularly laid block on the slope under the action of linear wave, and the stress duration curves at different points are given. The stress distribution at different times and the trend map of block movement are given, and the variation characteristics of stress inside the block are discussed. The numerical simulation results show that under the action of wave, the stress of contact point is the largest, and the joint part of the block limb is the second, and the stress of each point on the surface of the block changes periodically. The whole stability of the writhing block is good, it is not easy to occur local instability or global instability, and the movement trend of single block is mainly translation and roll. However, under extreme sea conditions, individual concrete blocks may be broken and destroyed in the joint of two limbs, which should be strengthened in engineering. The research work in this paper will provide reference for the design of breakwater surface block.
【學位授予單位】：大連理工大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：U656.2

【參考文獻】

相關期刊論文 前10條

1 李增志;別社安;任增金;;拋石防波堤穩(wěn)定性的離散單元法分析[J];工程力學;2009年S1期

2 任冰;金釗;高睿;賀銘;王永學;;波浪與斜坡堤護面塊體相互作用的SPH-DEM數值模擬[J];大連理工大學學報;2013年02期

3 John-Paul Latham;Antonio Munjiza;Julian Mindel;Romain Guises;Xavier Garcia;Chris Pain;Gerard Gorman;Matthew Piggott;;Modelling of massive particulates for breakwater engineering using coupled FEMDEM and CFD[J];Particuology;2008年06期

4 唐志平;胥建龍;;離散元與殼體有限元結合的多尺度方法及其應用[J];計算力學學報;2007年05期

5 胥建龍,唐志平;離散元與有限元結合的多尺度方法及其應用[J];計算物理;2003年06期

6 徐泳,孫其誠,張凌,黃文彬;顆粒離散元法研究進展[J];力學進展;2003年02期

7 劉凱欣,高凌天;離散元法研究的評述[J];力學進展;2003年04期

8 A. Munjiza;X. Garcia;J.P. Latham;G.G. Schiava D’Albano;N.W.M. John;;The Virtual Geoscience Workbench, VGW: Open Source tools for discontinuous systems[J];Particuology;2010年02期

9 俞聿修,柳淑學,朱傳華;多向不規(guī)則波作用下斜坡式建筑物護面塊體的穩(wěn)定性[J];海洋學報(中文版);2002年04期

10 謝世楞;斜坡式防波堤設計中若干問題的探討[J];水運工程;1983年01期

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