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  本文選題：炭質(zhì)板巖　切入點：干燥和飽水狀態(tài)　出處：《長安大學》2013年博士論文　論文類型：學位論文

【摘要】：開展不同含水狀態(tài)下巖石流變力學特性與模型研究，對于正確預測和有效控制巖石工程的安全與穩(wěn)定具有重要的理論價值和工程實踐意義。本文以蘭渝鐵路木寨嶺隧道炭質(zhì)板巖為研究對象，采用試驗研究、理論分析相結(jié)合的方法，基于炭質(zhì)板巖在干燥和飽水狀態(tài)下的力學特性以及蠕變規(guī)律，建立適用于炭質(zhì)板巖的非線性流變理論模型，結(jié)合粒子群算法(PSO)和非線性最小二乘法對流變參數(shù)進行辨識，并將建立的流變模型嵌入FLAC3D，完成數(shù)值程序的二次開發(fā)。本文主要研究工作如下： (1)開展干燥和飽和狀態(tài)下炭質(zhì)板巖單軸和三軸試驗、楔形剪切試驗、巴西圓盤劈裂試驗，以及單軸循環(huán)加卸載瞬時力學特性試驗，掌握了兩種狀態(tài)下炭質(zhì)板巖的瞬時力學特性，也為開展巖石蠕變試驗提供了試驗基礎(chǔ)。試驗結(jié)果表明：水對炭質(zhì)板巖強度和變形的影響是顯著的，而在單軸循環(huán)加卸載條件下的影響更為突出； (2)采用全自動伺服流變儀，對干燥和飽和炭質(zhì)板巖開展分級加載和分級增量循環(huán)加卸載蠕變試驗，研究兩種狀態(tài)下炭質(zhì)板巖的蠕變特點，以及水對巖石在各級壓力下的蠕變量、蠕變速率的影響。在中、低應力水平下，巖石蠕變變形主要呈現(xiàn)出衰減蠕變和穩(wěn)態(tài)蠕變2個階段，當加載應力增加到較高應力水平時，巖石軸向變形急劇增長，表現(xiàn)出加速蠕變階段；相同應力水平下的飽水巖樣的蠕變量為干燥巖樣的3倍以上；加卸載蠕變試驗表明：水對巖石瞬時變形的影響主要表現(xiàn)在瞬時塑性變形方面，對瞬時彈性變形的影響不大，而對巖石蠕變變形的影響則主要體現(xiàn)在粘彈性應變方面； (3)根據(jù)炭質(zhì)板巖在干燥和飽水狀態(tài)下的蠕變特點，在Burgers流變模型的基礎(chǔ)上，結(jié)合一個非線性粘塑性體，和Burgers流變模型相串聯(lián)，構(gòu)建適于炭質(zhì)板巖蠕變特點的改進Burgers非線性粘彈塑性流變模型，導出了模型的本構(gòu)方程、蠕變方程、卸載方程以及蠕變模型的三維形式； (4)在粒子群算法的基礎(chǔ)上，將線性遞減權(quán)重粒子群算法和Levenberg-Marqud非線性最小二乘法相結(jié)合，先采用線性遞減粒子群算法對流變模型參數(shù)進行初步辨識，將其結(jié)果作為初始值，再采用L-M算法進行辨識，參數(shù)辨識后的相關(guān)系數(shù)均在0.94以上； (5)針對目前建立的能反映蠕變加速階段的流變模型元件和參數(shù)較多的問題，借鑒經(jīng)典元件組合模型的建模思路，將含分數(shù)階微積分的軟體元件與彈簧元件串聯(lián)，結(jié)合一個冪函數(shù)粘塑性體，提出一種新的四元件非線性粘彈塑性流變模型，并給出該模型的本構(gòu)方程和蠕變方程。利用炭質(zhì)板巖蠕變試驗結(jié)果，將該模型與改進Burgers非線性流變模型進行對比擬合分析，表明該模型能夠有效地描述巖石的三階段蠕變特性，在滿足擬合精度的前提下，能夠減少組合模型中的元件個數(shù)和參數(shù)數(shù)量； (6)巖石的蠕變過程是巖石內(nèi)部應力不斷調(diào)整，硬化和損傷效應不斷發(fā)展并共同作用的結(jié)果。以經(jīng)典元件模型為基礎(chǔ)，將巖石的初始屈服強度作為蠕變硬化的應力閾值，巖石的長期強度作為損傷軟化的應力閾值，引入能反映巖石蠕變硬化的硬化函數(shù)和損傷效應的損傷變量，建立了一個能夠全面反映蠕變機制的巖石非線性蠕變模型。利用蠕變試驗數(shù)據(jù)對所提出的模型進行辨識，，結(jié)果表明該模型不僅能夠很好地描述三階段蠕變特性，而且可以全面反映巖石蠕變過程中的蠕變硬化和損傷軟化機制； (7)依據(jù)FLAC3D提供的內(nèi)置本構(gòu)模型源代碼，在Burgers蠕變模型有限差分形式的基礎(chǔ)上，導出了改進Burgers非線性蠕變模型的三維差分形式。借助C++語言將改進Burgers非線性蠕變模型的三維差分形式編譯成動態(tài)鏈接庫，嵌套到FLAC3D中，實現(xiàn)了本構(gòu)模型的二次開發(fā)，并利用新開發(fā)的流變模型進行單軸壓縮蠕變模擬試驗，驗證了程序二次開發(fā)的正確性。
[Abstract]:Study on characteristics and model of rock rheological mechanics under different moisture conditions, has important theoretical value and practical significance for the safety and stability of correct prediction and effective control of rock engineering. In this paper, Muzhailing tunnel on Lanzhou Chongqing railway carbonaceous slate as the research object, based on the experimental results, the theoretical analysis method of combining, carbon slate in mechanical properties of dry and saturated state and creep law based on nonlinear rheological theory model for carbonaceous slate, combined with particle swarm algorithm (PSO) on the rheological parameters identification and nonlinear least square method, embedded FLAC3D rheological model and the establishment of the completion of the two numerical procedure is developed. This paper the research work is as follows:
(1) to carry out dry and saturated carbonaceous slate single axis and three axis wedge test, shear test, Brazil disk split test, and uniaxial cyclic loading and unloading transient mechanical properties test, grasp the two conditions of carbonaceous slate instantaneous mechanical properties tests provide a basis for carrying out the creep test of rock. The experimental results show that the water has a distinct effect on the strength and deformation of the carbonaceous slate, the impact of the uniaxial cyclic loading and unloading conditions is more prominent;
(2) using automatic servo rheometer of dry and saturated carbonaceous slate to carry out graded loading and multi-step incremental cycling loading and unloading creep test, the creep characteristics of carbonaceous slate of two states, as well as at all levels under the pressure of water on rock creep, the creep rate of the impact. In the low stress under the rock creep deformation mainly presents 2 stages of decay creep and steady creep. When the loading stress increases to a higher stress level, axial deformation increased sharply, showing accelerated creep stage; under the same stress level of creep deformation of water saturated rock samples for dry rocks indicate that more than 3 times; unloading creep test: influence of water on rock instantaneous deformation mainly in instantaneous plastic deformation, has little effect on the instantaneous elastic deformation, and the influence on the creep deformation of rock is mainly embodied in the viscoelastic strain;
(3) according to the creep characteristics of carbonaceous slate in the dry and saturated state, based on Burgers rheological model, combined with a nonlinear viscoplastic body, and Burgers rheological model are suitable for constructing carbon slate creep characteristics of modified Burgers nonlinear visco elastoplastic rheological model, constitutive equation the model, derived creep equation, equation and three-dimensional form creep model;
(4) on the basis of particle swarm optimization, combining the linear decreasing weight PSO and Levenberg-Marqud nonlinear least square method, the linear decreasing particle swarm algorithm for preliminary identification of the parameters of rheological model, the results as the initial value, then the L-M algorithm for identification, parameter identification of the correlation coefficient in the more than 0.94;
(5) aiming at the establishment of the problem can reflect the accelerated creep rheological model of components and parameters more stage, from the classic element combination modeling ideas, the fractional calculus software element and spring element in series, with a power-law viscoplastic body, put forward a new four component nonlinear visco elasto plastic rheological model, and gives the model of the constitutive equation and creep equation. Using carbon slate creep test results, the model with improved Burgers nonlinear rheological model comparison fitting analysis show that the model can effectively describe the three stages of creep of rock, in order to meet the demand of the fitting precision, can reduce the the number of components and the number of parameters in the model;
(6) the creep process of rock is the rock internal stress hardening and damage effect of continuous adjustment, development and result of the interaction. Based on classical element model as the foundation, the rock initial yield strength as creep hardening stress threshold, the long-term strength of rock softening stress as the damage threshold, the damage variable can reflect the hardening function and damage effect of rock hardening, establish a fully reflect the creep mechanism of the nonlinear creep model of rock. To identify the model proposed by the creep test data, the results show that the model can well describe the creep characteristics of the three stage, but also can reflect the creep process of rock creep hardening and damage softening mechanism;
(7) on the basis of the built-in FLAC3D provides the constitutive model of the source code, in the Burgers creep model of finite difference based on improved Burgers derived three-dimensional nonlinear creep model of the three-dimensional form. The improved Burgers nonlinear creep model with the aid of the C++ language form is compiled into a dynamic link library, nested FLAC3D to achieve the two development, constitutive model, and the uniaxial compression creep simulation experiments using the new rheological model developed, verified the correctness of the two development program.

【學位授予單位】：長安大學
【學位級別】：博士
【學位授予年份】：2013
【分類號】：TU45

【引證文獻】

相關(guān)博士學位論文 前2條

1 楊文東;復雜高壩壩區(qū)邊坡巖體的非線性損傷流變力學模型及其工程應用[D];山東大學;2011年

2 陳文玲;黑河水庫壩肩邊坡云母石英片巖三軸蠕變機理及蠕變模型研究[D];長安大學;2009年

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