本文選題：統(tǒng)一強度理論　切入點：應(yīng)變局部化　出處：《長安大學(xué)》2013年博士論文　論文類型：學(xué)位論文

【摘要】：土體剪切帶的形成機理與應(yīng)變局部化理論是當(dāng)今國際力學(xué)界和巖土工程界廣泛研究的課題，應(yīng)變局部化分叉理論預(yù)測為揭示巖土材料的破壞機理提供了有力依據(jù)。統(tǒng)一強度理論具有統(tǒng)一的力學(xué)模型、統(tǒng)一的理論和統(tǒng)一的數(shù)學(xué)表達(dá)式，可以有規(guī)律地變化以適用于各類工程材料，形成了一系列有序的破壞準(zhǔn)則，可廣泛適用于各種工程領(lǐng)域。但統(tǒng)一強度理論在剪切帶形成機理以及非共軸本構(gòu)模型和應(yīng)變局部化分叉判別等方面還缺乏深入細(xì)致的系統(tǒng)應(yīng)用研究，而且以往應(yīng)變局部化沒有考慮三維應(yīng)力空間下混合硬化模型的影響。本文將混合硬化模型和統(tǒng)一強度理論用于應(yīng)變局部化應(yīng)力應(yīng)變關(guān)系，應(yīng)變局部化分叉點位置和剪切帶傾角等預(yù)測研究。主要研究內(nèi)容與結(jié)論如下： （1）建立了以壓應(yīng)力為正的統(tǒng)一強度理論公式，進(jìn)而推導(dǎo)了新的加載函數(shù)和相應(yīng)的塑性勢函數(shù)及本構(gòu)方程，并結(jié)合修正Euler積分方法編制了率型本構(gòu)方程的積分程序?qū)φ承酝疗矫鎽?yīng)變試驗和密砂真三軸試驗進(jìn)行了模擬和驗證，得出：當(dāng)參數(shù)b取合適值時，預(yù)測值比已有文獻(xiàn)結(jié)果更接近試驗結(jié)果。對于所選的粘性土材料和密砂材料，可分別選用參數(shù)b=1和b=0.9所對應(yīng)的強度理論進(jìn)行應(yīng)力應(yīng)變關(guān)系預(yù)測。 （2）在三維非共軸應(yīng)力空間內(nèi)，，考慮第三應(yīng)力不變量對塑性變形非共軸性的影響，基于非共軸混合硬化法則，建立了更加符合土體實際受力性狀的非共軸本構(gòu)新模型、變形局部化分叉點判別準(zhǔn)則和剪切帶傾角公式，并對所得結(jié)果進(jìn)行退化必要性驗證；同時，結(jié)合修正Euler積分的基本步驟進(jìn)行模擬，與已有成果和試驗數(shù)據(jù)進(jìn)行比較，驗證了所得分叉點判別準(zhǔn)則的初步合理性。 （3）建立了基于統(tǒng)一強度理論和混合硬化法則的新的加載函數(shù)、塑性勢函數(shù)、統(tǒng)一非共軸本構(gòu)模型、應(yīng)變局部化分叉點判別準(zhǔn)則和剪切帶傾角公式，并對粘性土平面應(yīng)變試驗和密砂真三軸試驗進(jìn)行了模擬和試驗驗證，得出：非共軸項的引入并不改變土體應(yīng)力應(yīng)變關(guān)系特性；對于所選的粘性土材料和密砂材料，可分別選用參數(shù)b=1和b=0.9所對應(yīng)的強度理論來分析預(yù)測應(yīng)變局部化分叉點和剪切帶傾角。
[Abstract]:The formation mechanism and strain localization theory of soil shear zone are widely studied in the field of international mechanics and geotechnical engineering. The prediction of strain localization bifurcation theory provides a force basis for revealing the failure mechanism of rock and soil materials. The unified strength theory has a unified mechanical model, a unified theory and a unified mathematical expression. Can be changed regularly to apply to all kinds of engineering materials, forming a series of orderly failure criteria, It can be widely used in various engineering fields. However, the unified strength theory is still lack of systematic research on shear band formation mechanism, noncoaxial constitutive model and strain localization bifurcation, etc. In the past, strain localization did not consider the effect of mixed hardening model in three-dimensional stress space. In this paper, the mixed hardening model and the unified strength theory are applied to the strain localization stress-strain relationship. Prediction of strain localization bifurcation point location and shear band inclination. The main contents and conclusions are as follows:. 1) the unified strength theory formula with compressive stress as positive is established, and a new loading function, corresponding plastic potential function and constitutive equation are derived. Combined with the modified Euler integral method, the integral program of the rate constitutive equation is compiled to simulate and verify the plane strain test of cohesive soil and the true triaxial test of dense sand. The predicted values are closer to the experimental results than the results of previous literatures. For the selected cohesive soil materials and dense sand materials, the stress-strain relationship can be predicted by the strength theory corresponding to the parameters bt1 and BX 0.9, respectively. 2) considering the influence of the third stress invariant on the non-coaxial deformation of the soil, a new noncoaxial constitutive model is established based on the non-coaxial mixed hardening rule in the three-dimensional non-coaxial stress space. The deformation localization bifurcation criterion and shear band inclination formula are used to verify the degenerative necessity of the obtained results. At the same time, combined with the basic steps of the modified Euler integral, the results are simulated and compared with the existing results and experimental data. The preliminary rationality of the bifurcation criterion is verified. A new loading function, a plastic potential function, a unified noncoaxial constitutive model, a strain localization bifurcation criterion and a shear band inclination formula are established based on the unified strength theory and the mixed hardening rule. The plane strain test of cohesive soil and the true triaxial test of dense sand are simulated and verified. It is concluded that the introduction of non-coaxial term does not change the stress-strain relationship of soil, and for the selected cohesive soil and dense sand, The strength theory corresponding to the parameters bt1 and bt0. 9 can be used to analyze and predict the strain localization bifurcation point and shear band inclination respectively.
【學(xué)位授予單位】：長安大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2013
【分類號】：TU43

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 董建國,袁聚云;局部變形及基坑圍護(hù)理論的探討[J];地下空間與工程學(xué)報;2005年04期

2 張啟輝,李蓓,趙錫宏,董建國;上海粘性土剪切帶形成的平面應(yīng)變試驗研究[J];大壩觀測與土工測試;2000年05期

3 周健,池永;土的工程力學(xué)性質(zhì)的顆粒流模擬[J];固體力學(xué)學(xué)報;2004年04期

4 甄文戰(zhàn);孫德安;;砂的臨界狀態(tài)本構(gòu)模型局部化分叉分析[J];水利學(xué)報;2011年05期

5 俞茂宏,Oda Y,盛謙,沈俊,顧金才,李小春,李慶斌,周小平,蔣鎖紅,張永興,董毓利,劉繼明,景宏君,Yoshimine M,徐栓強;統(tǒng)一強度理論的發(fā)展及其在土木水利等工程中的應(yīng)用和經(jīng)濟意義[J];建筑科學(xué)與工程學(xué)報;2005年01期

6 俞茂宏,昝月穩(wěn),范文,趙堅,董正筑;20世紀(jì)巖石強度理論的發(fā)展——紀(jì)念Mohr-Coulomb強度理論100周年[J];巖石力學(xué)與工程學(xué)報;2000年05期

7 錢建固;黃茂松;;復(fù)雜應(yīng)力狀態(tài)下巖土體的非共軸塑性流動理論[J];巖石力學(xué)與工程學(xué)報;2006年06期

8 姚仰平;侯偉;羅汀;;土的統(tǒng)一硬化模型[J];巖石力學(xué)與工程學(xué)報;2009年10期

9 董建國,李蓓,袁聚云,趙錫宏;上海淺層褐黃色粉質(zhì)粘土剪切帶形成的試驗研究[J];巖土工程學(xué)報;2001年01期

10 錢建固,黃茂松;土體變形分叉的非共軸理論[J];巖土工程學(xué)報;2004年06期

相關(guān)博士學(xué)位論文 前3條

1 張東明;巖石變形局部化及失穩(wěn)破壞的理論與實驗研究[D];重慶大學(xué);2004年

2 劉金龍;巖土應(yīng)變局部化的有限單元理論與應(yīng)用[D];武漢大學(xué);2005年

3 甄文戰(zhàn);巖土材料變形局部化問題理論及數(shù)值分析研究[D];上海大學(xué);2010年

本文編號：1646004