本文關(guān)鍵詞：邢衡高速路基軟土的微結(jié)構(gòu)本構(gòu)模型　出處：《河北工業(yè)大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 軟土 微結(jié)構(gòu) PFC 彈塑性 本構(gòu)模型

【摘要】：近年來國內(nèi)經(jīng)濟(jì)建設(shè)越來越發(fā)達(dá),各種各樣的建筑層出不窮,且大部分建筑物位于濱海相或湖泊相分布較廣的軟土地區(qū),由軟土帶來的地質(zhì)災(zāi)害等現(xiàn)象越來越受到關(guān)注。而軟土具有微觀結(jié)構(gòu)性,所以使用目前已經(jīng)發(fā)展成熟的模型來估算軟土的變形量時(shí),那些模型得出的估算結(jié)果與實(shí)測數(shù)值相比并不一致,因此在針對(duì)軟土特性的分析中,考慮微觀特征的軟土本構(gòu)模型成為當(dāng)下備受關(guān)注的課題。本文中依托邢衡高速軟土,對(duì)軟土的微結(jié)構(gòu)本構(gòu)模型進(jìn)行了分析。本文展開的工作包括以下內(nèi)容和結(jié)論:1、通過對(duì)邢衡高速路基軟土原狀土進(jìn)行室內(nèi)土工試驗(yàn)和電鏡掃描試驗(yàn),得出基本物理力學(xué)性質(zhì)和SEM圖像。進(jìn)而得出邢衡高速路基軟土原狀土的孔隙孔徑分布、孔隙微結(jié)構(gòu)定量參數(shù)、顆粒微結(jié)構(gòu)定量參數(shù),并且針對(duì)不同應(yīng)力狀態(tài)下的試樣垂直面和水平面的SEM圖片即微觀電鏡掃描照片作出了定量分析及比對(duì),揭示了土體變形過程中土體顆粒和孔隙的變化規(guī)律,從而在微觀上闡述土體發(fā)生宏觀變形的規(guī)律。2、運(yùn)用顆粒流程序PFC對(duì)標(biāo)準(zhǔn)固結(jié)試驗(yàn)和常規(guī)三軸試驗(yàn)進(jìn)行了仿真模擬,得出了應(yīng)力應(yīng)變曲線,通過將數(shù)值模擬結(jié)果與實(shí)測試驗(yàn)結(jié)果對(duì)比發(fā)現(xiàn)PFC內(nèi)置接觸本構(gòu)模型都能夠在一定程度上反映出實(shí)際土樣的本構(gòu)關(guān)系。3、基于目前工程中常用的本構(gòu)模型建立了軟土的微結(jié)構(gòu)本構(gòu)模型。假設(shè)軟土顆粒接觸面上的屈服準(zhǔn)則服從以摩爾庫倫準(zhǔn)則為基礎(chǔ)的彈塑性準(zhǔn)則。彈性部分通過赫茲麥德林準(zhǔn)則求出,塑性部分通過引入一個(gè)錐狀屈服面反映其特性。通過“優(yōu)化假設(shè)方法”實(shí)現(xiàn)微觀顆粒接觸面上的位移到宏觀應(yīng)變的轉(zhuǎn)化,然后通過能量守恒的方法實(shí)現(xiàn)微觀接觸面上的力到宏觀應(yīng)力的轉(zhuǎn)化。然后運(yùn)用標(biāo)準(zhǔn)固結(jié)試驗(yàn)和常規(guī)三軸試驗(yàn)數(shù)據(jù)對(duì)本構(gòu)模型進(jìn)行了驗(yàn)證,所得的模型可以在微觀層面描述出土體的宏觀的本構(gòu)關(guān)系,模型計(jì)算得出的結(jié)果與試驗(yàn)實(shí)測數(shù)據(jù)相比對(duì)表明一致性。
[Abstract]:In recent years, the domestic economy developed more and more, all kinds of buildings in soft soil area and emerge in an endless stream, most of the buildings in coastal or lake facies is widely distributed, and brought by soft soil geological disasters such as the phenomenon of more attention. The soft soil with micro structure, so the use of the current mature model to estimate the deformation the amount of soft soil, the estimation results derived from the model and the measured value is compared is not consistent, so the analysis for soft soil characteristics, constitutive model has become the topic of concern in soft soil microstructure characteristics are considered. This paper based on the high speed soft soil micro structure of Xing Heng, soft soil constitutive model the analysis. The main work includes the following contents and conclusions: 1, through indoor soil test and SEM test of high-speed Xing Heng Subgrade in soft soil undisturbed soil, obtained the basic physical and Mechanical The nature and SEM image. Then we can get the pore size distribution of high speed Xing Heng soft roadbed soil, pore micro structure quantitative parameters, particle microstructure quantitative parameters, and according to the different stress state of specimen of vertical surface and horizontal surface SEM picture: micro scanning electron microscope photos made quantitative analysis and comparison, reveals the change the deformation of soil particles and pores of soil, so the soil macro deformation regularity of.2 in the micro level, using particle flow code PFC on the standard consolidation test and the conventional three axis test simulation, the stress-strain curve, the numerical simulation results and the actual test results found in PFC contact constitutive model can reflect the actual.3 constitutive relation of soil to a certain extent, based on the commonly used constitutive model of micro structure of soft soil constitutive model in Engineering Type. Assuming yield criterion of soft soil particles on the surface of the contact to obey Moore in Kulun criterion based elastic-plastic elastic criterion. Part of the Medellin criteria for Hertz, plastic parts introduce a cone yield surface reflects its characteristics. Through the optimization of "transformation assumption method" to achieve the displacement of microscopic particles on contact surface. To the macroscopic strain, and then into the macro stress by the method of energy conservation to achieve micro contact surface force. Then using the verification of the constitutive model for standard consolidation test and conventional three axis test data, the model can describe the soil macro constitutive relation at the micro level, the calculation results of the model the results show that compared with the experimental data for consistency.

【學(xué)位授予單位】：河北工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：U416.1

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 孫紅,葛修潤,蒲毅彬,牛富俊,馬巍;三軸應(yīng)力條件下上�；疑惩恋腃T細(xì)觀試驗(yàn)研究[J];巖土力學(xué);2004年09期

，

本文編號(hào)：1379117