岩石破坏过程中的损伤统计本构模型

统计损伤力学是依据岩石破坏过程中的三轴试验资料反推其本构关系的一种有效手段。假定岩石微元强度服从幂函数分布的概率分布理论,将Hoek-Brown强度准则作为岩石统计分布变量,建立了岩石损伤变量演化方程和岩石在三维应力作用下的损伤统计本构模型,并用试验资料对其进行了验证。通过将理论结果和试验结果进行对比发现：该模型能够比较好的反映岩石的本构关系和破坏过程,从而说明了模型的合理性和可行性;模型分布参数R反映了岩石的强度,m反映了岩石的强度和脆性程度,但二者不是相互独立的,而是具有内在联系的。     

脆性岩石非线性弹性损伤本构方程及其实验验证

本文在对脆性岩石力学性质的实验研究的基础上,探讨了脆性岩石的广义弹性模量,广义弹性泊松比,不可逆变形泊松比以及岩石的损伤变形特征,从而定义了新的岩石损伤表征量.建立了脆性岩石的弹性损伤耦合本构方程和损伤演化方程.并采用石英砂岩对所建立的岩石损伤本构方程在单轴压缩实验中进行验证,结果表明,理论分析与实验结果吻合较好.     

基于多场耦合分析的磁流变阻尼器建模与结构参数影响

为了建立准确的阻尼器出力模型,在Bingham黏塑性模型的基础上增加线性弹簧单元描述磁流变液的黏弹塑性. 以双出杆剪切阀式磁流变阻尼器为研究对象,将上述模型引入多场耦合仿真中,结合磁场仿真得到的非均匀动态磁场,可得磁流变液的表观黏度分布,处理得到阻尼器在不同的输入激励与电流下的动态特性. 研究结果表明,相较于并联本构,依据串联本构建立的磁流变阻尼器仿真模型与试验结果具有更好的一致性. 根据理论与仿真分析各结构参数对阻尼器磁场及阻尼器出力及其可调范围的影响,计算各参数对阻尼器出力的灵敏度. 结果表明,阻尼间隙与活塞直径对阻尼器的出力影响较大,其中活塞直径的影响最大,峰值灵敏度指标与均值灵敏度指标分别为84.66%和94.51 N.     

Rheological constitutive model of rock mass based on viscoplastic theory

With many major projects under construction,more and more attention is paid to rheological mechanical properties of rock mass,and extensive researches are carried out for rheological constitutive modeling of rock mass.Based on viscoplastic theory,a new rheological constitutive model is proposed.The rationality and validity of proposed model are verified through the creep test data.The results show that the rheological constitutive model based on viscoplastic theory is able to simulate the typical creep curves of rock mass and the identified parameters are reasonable.Therefore,the rheological constitutive model could be used to describe the rheological mechanical behaviour of rock mass.     

软岩地下洞库施工的水土耦合有限元模拟

为了解决饱和软岩地下洞库开挖稳定数值模拟分析中的2项关键问题：合适的本构模型和超孔隙水压对岩体受力变形的影响,基于软岩的类超固结土性质,将下负荷面理论应用于修正剑桥模型,推导出适用于研究软岩地层开挖数值模拟的简易本构模型,并通过三轴试验结果与数值模拟结果相比较验证新本构模型的适用性;然后通过某一实际软岩地下洞库开挖工程的数值模拟,对比分析水土耦合和水土非耦合方法得到的数值模拟结果与现场实测结果间的符合程度.结果表明,新提出的所需参数较少的简易软岩本构模型能较好地模拟岩体在开挖过程中的受力变形特征,同时发现采用水土耦合算法模拟饱和软岩地下洞室开挖能够很好地模拟实际开挖过程中围岩的受力与变形情况.     

Seepage-stress coupling constitutive model of anisotropic soft rock

To provide a seepage-stress coupling constitutive model that can directly describe the seepage-stress coupling relationship, a series of one-dimensional seepage-stress coupling tests on two kinds of soft rock (argillaceous siltstone and brown mudstone) were performed by using an MTS-815.02 tri-axial rock mechanics test system, with which the stress—strain curves according to the seepage variation were obtained. Based on the experimental results and by employing Hooke’s law, the formulation of the coefficient of strain-dependent permeability was presented and introduced to establish a coupling model. In addition, the mathematical expression and the incremental formulation for coupling model were advanced, in which five parameters that can be respectively determined by using the experimental results were included. The calculated results show that the proposed coupling model is capable of simulating the stress—strain relationship with considering the seepage-stress coupling in the nonlinear elastic stage of two kinds of soft rock. Foundation item: Projects(50378069, 50639090) supported by the National Natural Science Foundation of China; Project(50639090) supported by the Joint Fund of Yalong River Hydropower Development, China     

岩石动载损伤破坏的研究进展

自从1976年Dougill将损伤力学引入岩石材料的研究中以来,岩石动载损伤破坏的研究已成为岩石力学领域重要研究课题之一,并且在许多行业中应用。概述了岩石动载损伤破坏实验的研究、破坏特性、能量损耗、损伤破坏模型及本构方程的发展,提出了水中爆炸激波对饱和水泥试样冲击损伤的初步研究成果。     

Numerical simulation of triaxial compression test for brittle rock sample using a modified constitutive law considering degradation and dilation behavior

The understanding of the rock deformation and failure process and the development of appropriate constitutive models are the basis for solving problems in rock engineering. In order to investigate progressive failure behavior in brittle rocks, a modified constitutive model was developed which follows the principles of the continuum damage mechanics method. It incorporates non-linear Hoek-Brown failure criterion, confining pressure-dependent strength degradation and volume dilation laws, and is able to represent the nonlinear degradation and dilation behaviors of brittle rocks in the post-failure region. A series of triaxial compression tests were carried out on Eibenstock(Germany) granite samples. Based on a lab data fitting procedure, a consistent parameter set for the modified constitutive model was deduced and implemented into the numerical code FLAC3 D. The good agreement between numerical and laboratory results indicates that the modified constitutive law is well suited to represent the nonlinear mechanical behavior of brittle rock especially in the post-failure region.     

具有滞环的非线性非自治电路唯一稳态研究

目前已有的研究结果表明,如果电路中元件的成分关系是单值的并且是严格递增的（即斜率为正）,则对于不同的电路可以得到不同的保证电路具有唯一稳态的条件。然而对于电路元件为多值函数（例如含滞环）的情况,目前还没有相应的结果。采用一种新的方法,即向量比较法,建立了确定具有滞环的非线性非自治电路唯一稳态的条件。结果表明,具有滞环的非线性非自治电路的唯一稳态,可以用一个常数矩阵的Hurwitz条件来决定。这一结果适用于含有任意个滞环元件的非线性非自治电路。通过算例验证,表明本文的理论预测是正确的。     

Stochastic structural model of rock and soil aggregates by continuum-based discrete element method

Ancient slope[1], debris-flow deposit[2] and rock-filling dam[3] are usually made of rock and soil aggregates (RSA). The RSA is a typical inhomogeneous and discontinuous medium, and its main characteristics include: (i) loose piling up by blocks or particles, (ii) mixing of different blocks with a range of shapes and sizes, (iii) stochastic distribu- tion of blocks in space, (4) fillings often in between blocks. The mechanical properties of these rock and soil aggregates are commonly obtaine…     

隧道围岩变形预报的高斯过程机器学习模型

针对隧道围岩变形过程是一个高度复杂的非线性时间序列的问题,以隧道围岩变形历史资料作为知识源,通过构建围岩变形时间序列,采用高斯过程模型建立隧道围岩当前变形与历史变形的非线性映射关系,在此基础上分别提出了基于静态知识库与基于动态知识库的隧洞围岩变形预报的高斯过程模型。工程实例应用研究表明,围岩变形预报的高斯过程机器学习模型是可行的,无需建立复杂的岩体力学模型,根据历史实测资料就能够对隧道围岩变形做出合理预报,与基于静态知识库的高斯过程模型相比较,基于动态知识库的高斯过程模型的预报精度更高。     

Stochastic structural model of rock and soil aggregates by continuum-based discrete element method

This paper first presents a stochastic structural model to describe the random geometrical features of rock and soil aggregates. The stochastic structural model uses mixture ratio, rock size and rock shape to construct the microstructures of aggregates, and introduces two types of structural elements (block element and jointed element) and three types of material elements (rock element, soil element, and weaker jointed element) for this microstructure. Then, continuum-based discrete element method is used to study the deformation and failure mechanism of rock and soil aggregate through a series of loading tests. It is found that the stress-strain curve of rock and soil aggregates is nonlinear, and the failure is usually initialized from weaker jointed elements. Finally, some factors such as mixture ratio, rock size and rock shape are studied in detail. The numerical results are in good agreement with in situ test. Therefore, current model is effective for simulating the mechanical behaviors of rock and soil aggregates.     

Effect of Engineering Character on Stress-Strain Relationship in Post-Peak Area

Constitutive experiments are the base of all rock mechanics works. The effect of engineering character on constitutive law is a new problem of rock mechanics. The results of series specimens based on the uniaxial and plane strain compression experiments were presented and discussed. It is found that engineering or experiment character has obvious effects on stress-strain relationship and especially on mechanic parameters in post-peak area. And the law of size effect of softening materials was also discussed.     

不同倾角节理岩体损伤演化特征分析

为研究节理倾角对岩体损伤的影响规律,运用损伤力学理论建立考虑节理与荷载共同作用的岩体损伤演化模型及损伤本构模型;通过单弱面理论对模型试验进行验证,同时探讨节理岩体损伤演化特征.结果表明:单弱面理论结果与试验结果较为吻合,模型试验能较好地表征含单一结构面的岩体在荷载作用下的力学特征及损伤演化规律;当节理倾角从0增大到90°过程中,初始节理损伤先增后减,在倾角为60°时至最大值,总体呈倒"U"型分布规律;不同倾角节理岩体总损伤演化规律基本一致,均呈"S"型分布规律,先缓慢增加,而后快速增加,最后再缓慢增加其值趋于1;节理倾角只影响总损伤率数值大小不影响其演化规律,总损伤率随应变增加呈正态分布;总损伤率受控于节理面分布规律,当节理倾角从0增大至90°的过程中,总损伤率先减小后增大.     

碳酸二甲酯生产流程仿真培训系统

仿真培训系统是计算机仿真的重要应用领域之一。仿真培训系统以其逼真、低耗、安全和规范化培训等特点，在学员培训中取得了显著效果，而且已在重要工业部门的复杂操作岗位的人员培训中被推广和使用。建立了碳酸二甲酯仿真培训系统单元数学模型，介绍了该系统的组成，以及该系统的功能、特点和运行模式。     

卸荷岩体力学的研究与发展

卸荷岩体力学是常规岩体力学的有益补充,其力学特性与加载岩体力学有本质区别.近十几年来,卸荷岩体力学已在宏观力学参数选取、破坏机理以及本构模型研究方面得到了很大的发展,但在以后的研究中更应加强破坏的细观机理、时效性和多场耦合性的研究.     

基于Mohr准则的岩石损伤本构模型及其修正研究

基于Mohr准则,重新定义了岩石微元强度。考虑岩石微元强度服从随机分布的特点,结合损伤力学理论和统计强度理论,建立了三轴压缩条件下岩石损伤本构模型。为使建立的模型更具一般性,分析了模型参数与围压的关系,并据此对模型参数进行合理修正,从而建立出完整的岩石损伤本构模型。与试验结果比较,所建模型可以灵活地模拟各级围压下岩石破裂过程的全应力应变关系,尤其是应变软化特性。同时,该模型形式简单,应用方便,接近工程实际。     

考虑渗压的二长花岗岩流变损伤本构模型研究

基于二长花岗岩的流变试验结果,采用Cross-plotting方法确定了有效应力系数,在广义Bingham模型的基础上建立了考虑渗透压力损伤的流变损伤本构模型,对新的流变损伤模型进行参数辨识,得到了流变损伤模型的参数。推导了模型的流变本构方程,并用该模型拟合了岩石流变试验的数据,拟合结果表明:该模型不仅可以很好地描述衰减流变和稳态流变过程,亦可描述岩石的加速流变阶段,从而证明该模型的可行性和合理性。     

椭圆水泥环厚度和弹性模量对套管受力的影响分析

根据岩石力学和弹塑性力学理论,建立套管-水泥环-地层力学模型,采用有限元方法研究分析不同地应力条件下椭圆水泥环厚度和弹性模量对套管应力的影响,研究结果表明：在均匀地应力条件下,一定厚度的圆形水泥环对减小套管受力有益,在非均匀地应力条件下,采用椭圆水泥环能有效的减小套管应力．     

两轮直立式自平衡移动机器人的控制系统设计

研究了两轮直立式自平衡机器人的系统组成,并利用动力学原理建立系统的数学模型,在Matlab环境下设计了状态反馈控制器(LQR),并进行了仿真和机器实体的实验,系统具有良好的鲁棒性.表明了系统建模和控制器设计的合理性和有效性.这种机器人两轮共轴、独立驱动,车身重心倒置于车轮轴上方,通过运动保持平衡,可直立行走.由于特殊的结构,其适应地形变化能力强,运动灵活,可以胜任一些复杂的工作.为机器人的自主控制、自学习提供了可靠的实验平台.