围岩与衬砌复合体的粘弹性分析

本文在平面应变条件下,对粘弹性圆形巷道和衬砌的耦合问题进行分析,衬砌(粘弹或弹性的)是在巷道开挖后,或巷道形成后经过一段时间蠕变才加上的。使用积分型粘弹本构关系——Boltzmann记忆积分求出围岩和衬砌的位移,然后根据它们交界面处的连续条件,得到位移围岩和衬砌交界面上支护反力为未知量的积分方程。最后,对一些具体情况由积分方程求得支护反力,从而得到围岩和衬砌的位移和应力,并对其进行了分析。     

冲压成形过程的弹粘塑性有限元数值模拟

应用单轴应力状态下的弹粘塑性本构关系和J2 流动理论及等向强化准则建立起适用于多轴应力状态的普遍的弹粘塑性本构关系 ,并将其引入增率型虚功率原理建立了弹粘塑性有限元列式。用基于该组列式编制的大变形有限元程序对单拉过程和方盒件深拉延成形过程进行了数值模拟 ,并与单拉实验结果进行了比较。数值模拟结果表明 :本文建立的弹粘塑性材料的本构关系是有效的 ,同时说明根据增率型虚功率原理建立的弹粘塑性有限元列式可以有效地对弹粘塑性变形过程进行数值模拟。     

单向应力状态下线性强化弹粘塑性材料的流变性质

分析了单向应力状态下线性强化弹粘塑性材料的流变性质,指出了这种材料的本构方程与粘弹性三参量固体的本构方程相似性,从而得出了积分型本构方程.     

基于长期强度的节理岩体洞室蠕变特性研究

为了进一步探究节理岩体蠕变特性,摆脱传统意义上从宏观弹塑或粘弹塑本构的角度分析岩体流变特性的方法,将细观单元视为弹脆性的本构关系,采用考虑岩石长期强度的岩石破裂过程分析系统,通过对不同工况下的节理岩体洞室数值模拟,得到了节理间距和节理夹角对围岩蠕变特性及其破坏特征的影响规律。结果表明：节理岩体洞室围岩的蠕变量随着节理面间距的增大而减小;当节理面的水平夹角小于45°时,节理岩体洞室围岩蠕变量随着节理面夹角的增大而增大,但当节理面倾角大于45°时,蠕变量反而随着节理面倾角的增大而减小,当节理面倾角等于45°时,围岩出现大量破坏,并表现出加速蠕变的特征。     

矩形和直墙拱断面围岩巷道破坏的数值模拟研究

通过对岩石破坏特性和机理的分析,得出岩石破坏的剪切强度与参数的数学关系。在此基础上建立围岩巷道的数值模型,模拟围岩巷道在矩形和直墙拱等断面条件下的破坏过程,得出巷道在不同侧压系数条件下的围岩破坏特征。结果表明:同一断面形状,当侧压系数较小时,破坏裂纹首先出现在两帮,随着荷载的增大,破坏裂纹由底部向顶部转移;另外基于矩形和直墙拱形断面巷道的数值模拟,得出了围岩巷道的破坏是一个渐进的过程,并伴随应力场而不断转移,且在相同侧压系数和外荷载条件下,矩形巷道破坏较为严重。分析矩形巷道和直墙拱巷道变形破坏过程,为合理寻求巷道设计和支护方法提供依据。     

不同断面形式深埋巷道围岩破坏数值模拟分析

以Ⅲ级围岩为例,利用有限差分软件FLAC对不同埋深情况下不同断面形式的巷道进行数值模拟,分析矩形、直墙拱形和圆形断面巷道围岩应力应变、围岩塑性区随埋深的变化规律及特点。结果表明：拱形断面巷道的围岩变形、围岩塑性区最小,尤其是顶板下沉量较矩形和圆形断面巷道的要小得多;圆形断面巷道围岩水平向位移最小;矩形断面巷道围岩应力及变形随埋深增加幅度都要大于拱形和圆形断面巷道。     

多断面巷道表面收敛快速观测方法研究

通过分析巷道掘进期间围岩表面收敛的规律,得出了多断面巷道表面收敛的快速矿压观测方法.其本质在于在巷道围岩状况相似、支护方式一致、施工速度和质量相同的地点可按不同距离布置多个断面,进行顶底板和两帮宽度的观测,通过空间来换取时间,在较短时间内得出巷道收敛的规律.掘进工作面推进速度较快或巷道矿压显现程度较低的巷道,观测时断面的数量可设置少些,距离可大些,否则应设置更多断面并减少距离.该方法在某矿煤层回风大巷得到了具体应用,通过对间距20～30 m不等的5个断面一周时间的观测后,成功得出了整条巷道26 d内表面收敛及收敛速度的变化规律,为常规观测时间的1/4左右.     

沥青混合料粘弹塑性本构关系及大变形有限元分析一般理论

应用Perzyna’s理论和Mises屈服准则建立沥青混合料粘弹塑性本构方程,并扩展到三维方程;应用Newton-Raphson迭代程序的逐步积分方法,获得了小变形粘弹塑性本构理论增量形式和有限元数值方程。基于小变形本构理论,把其应力应变、应力偏量和等效应力分别改用Cauchy应力的Jaumann导数、变形率、应力偏量和等效应力,推导出大变形粘弹塑性增量形式的本构方程和数值方程,建立了沥青混合料粘弹塑性理论体系。     

巷道围岩蝶形破坏理论的适用性分析

蝶形破坏理论为定量研究地下围岩力学行为及解决地下工程灾害提供新的思路和方法.针对业内专家学者对蝶形破坏理论重点关心的问题展开研究,通过理论分析与数值模拟分析了理论计算的可靠性,以及蝶形破坏理论在不同巷道断面形状、层状围岩条件下的适用性.结果表明:1)理论计算与数值模拟得到的塑性区的形态与发展规律完全一致,仅在塑性区范围计算精度上有所差别,理论公式在研究巷道围岩力学行为规律方面具有可靠性;2)不同巷道断面形状围岩的蝶形破坏具有相似性,理论计算得到的蝶形破坏规律在非圆形断面条件下仍然适用;3)在层状围岩条件下岩层之间性质的差异导致巷道围岩蝶形破坏表现出选择性,但蝶形显现部位仍然符合蝶形破坏的数学界定,因此蝶形破坏理论在层状围岩条件下仍然适用.     

煤矿巷道断面形状及锚杆支护围岩变形的数值分析

为了研究巷道不同断面形状和锚杆支护对巷道围岩稳定性的影响,采用ANSYS有限元计算方法进行数值模拟,通过对计算结果分析,得出半圆拱形巷道为最佳断面且煤矿巷道锚杆支护能够有效地控制围岩的变形;煤矿巷道锚杆支护对竖向位移的控制作用较大的区域集中在巷道围岩1.8 m范围以内及巷道的两个底角部;对于横向位移的控制作用较大的区域集中在巷道围岩顶板、两帮中部1.6 m范围以内及巷道的两个底角部.     

巷道层状围岩介质中稳恒电流场的边界积分解

巷道层状围岩介质中稳恒电流场分布规律是矿井直流电法勘探的理论基础．选取无巷道层状介质模型全空间电位函数为基本解，导出了巷道层状围岩介质中电流场的边界积分方程，为采用边界元法正演计算井下稳恒电流场场分量提供了理论和方法．     

Analytical solution for a circular roadway considering the transient effect of excavation unloading

The rocks surrounding a roadway exhibit some special and complex phenomena with increasing depth of excavation in underground engineering.Quasi-static analysis cannot adequately explain these engineering problems.The computational model of a circular roadway considering the transient effect of excavation unloading is established for these problems.The time factor makes the solution of the problem difficult.Thus,the computational model is divided into a dynamic model and a static model.The Laplace integral transform and inverse transform are performed to solve the dynamic model and elasticity theory is used to analyze the static model.The results from an example show that circumferential stress increases and radial stress decreases with time.The stress difference becomes large gradually in this progress.The displacement increases with unloading time and decreases with the radial depth of surrounding rocks.It can be seen that the development trend of unloading and displacement is similar by comparing their rates.Finally,the results of ANSYS are used to verify the analytical solution.The contrast indicates that the laws of the two methods are basically in agreement.Thus,the analysis can provide a reference for further study.     

Deformation mechanism and stability control of roadway along a fault subjected to mining

It is difficult to maintain the roadway around a fault because of the fractured surroundings, complex stress environment, and large and intense deformation in the mining process. Based on a tailgate of panel S2205 in Tunliu colliery, in Shanxi province, China, we investigated the evolution of stress and displacement of rocks surrounding the roadway during the drivage and mining period using theoretical analysis, numerical simulation and field trial methods. We analyzed the deformation and failure mechanisms of the tailgate near a fault. The deformation of surrounding rock caused by unloading in the drivage period is large and asymmetric, the roadway convergence increases with activation of the fault and secondary fracture develops in the mining period. Therefore, we proposed a specific control technique of the roadway along a fault as follows: (1) High-strength yielding bolt not only supports the shallow rock to load-bearing structures, but also releases primary deformation energy by use of a pressure release device in order to achieve high resistance to the pressure retained; (2) Grouting of near-fault ribside after initial stabilization of the rock deformation is used to reinforce the broken rock, and to improve the integral load-bearing capacity of the roadway. The research results were successfully applied to a field trial.     

Spatiotemporal evolution rule of rocks fracture surrounding gob-side roadway with model experiments

A series of plane-strain physical model experiments are carried out to study the spatiotemporal evolution rule of rocks fracture surrounding gob-side roadway, which is subjected to the pressure induced by the mining process. The digital photogrammetry technology and large deformation analysis method are applied to measure the deformation and fracture of surrounding rocks. The experimental results indicate that the deformation and fracture of coal pillars are the cause to the instability and failure of the surrounding rocks. The spatiotemporal evolution rule of the rock deformation and fracture surrounding gob-side roadway is obtained. The coal pillar and the roof near coal pillar should be strengthened in support design. The engineering application results also can provide a useful guide that the combined support with wire meshes, beam, anchor bolt and cable is an effective method.     

松软巷道注浆加固堵水技术的应用

中马村煤矿因巷道支护形式等与动水条件下的巷道压力不匹配而使巷道破坏造成大面积突水．通过对巷道破坏及突水机理分析,确定在巷道突水地区采用浅部围岩注浆提高围岩强度和深孔高压注浆封水相结合的注浆方式,能有效控制围岩变形破坏,实现堵水目的．     

破裂状态围岩巷道变形量计算的几何方法

基于岩石破裂后体积膨胀和巷道变形主要是由破裂区围岩体积膨胀引起的事实,提出了一种新的巷道变形量计算法——几何计算法．新方法根据破裂区围岩破裂膨胀前后的体积关系确定巷道变形量,适用于任何断面形状的巷道．     

Rules of distribution in a plastic zone of rocks surrounding a roadway affected by tectonic stress

In order to study the rules of distribution in a plastic zone of rocks, surrounding a roadway, affected by tectonic stress, we first analyzed the mechanics of a roadway affected by tectonic stress and derived a theoretical formula for the plastic zone of rocks surrounding a roadway. We also analyzed the distribution characteristics of the plastic zone under different levels of tectonic stress, vertical pressure, cohesion and friction angle of the surrounding rock. Secondly, we used numerical simulation to analyze the range and shape features of the plastic zone of rocks surrounding the roadway, given different tectonic stress levels. Finally we used a rock drilling detector to carry out field measurements on the broken state of rock surrounding the roadway at the -700 substation and channels in the Xinzhuang mine of the Shenhuo mining area. Given the measured ground stress, we analyzed the relationship between tectonic stress and the distribution of this plastic zone. Our results show that the range of the plastic zone at the top and bottom of the roadway increases with an increase in tectonic stress and this increase is especially obvious at the roadway comer.     

深部巷道围岩控制原理与应用研究

采用理论分析、数值模拟和现场试验的方法，研究深部巷道围岩稳定问题，认为深部巷道围岩控制的基本方法是提高围岩强度、转移围岩高应力以及采用合理的支护技术．提出了深部巷道围岩控制的基本技术和控制过程：1）应力转移降低巷道浅部围岩应力；2）采用高预紧力、大延伸量的高强度锚杆、锚索支护系统，强化锚固区围岩强度，提高巷道围岩自身稳定性；3）加强巷道两帮、底角支护，提高巷道最薄弱部位（两帮、底角）残余强度、提高巷道围岩的整体稳定性；4）应用高水速凝材料注浆加固破碎区，提高破碎围岩的完整性和力学参数．该研究成果已成功应用于工程实践．     

松软巷道注浆加固堵水技术的应用

中马村煤矿因巷道支护形式等与动水条件下的巷道压力不匹配而使巷道破坏造成大面积突水 .通过对巷道破坏及突水机理分析 ,确定在巷道突水地区采用浅部围岩注浆提高围岩强度和深孔高压注浆封水相结合的注浆方式 ,能有效控制围岩变形破坏 ,实现堵水目的 .     

Physical model test and numerical simulation on the failure mechanism of the roadway in layered soft rocks

To explore the failure mechanism of roadway in layered soft rocks, a physical model with the physically finite elemental slab assemblage(PFESA) method was established. Infrared thermography and a video camera were employed to capture thermal responses and deformation. The model results showed that layered soft roadway suffered from large deformation. A three-dimensional distinct element code(3 DEC) model with tetrahedral blocks was built to capture the characteristics of roadway deformation,stress, and cracks. The results showed two failure patterns, layer bending fracture and layer slipping after excavation. The layer bending fracture occurred at positions where the normal direction of layers pointed to the inside of the roadway and the layer slipping occurred in the ribs. Six schemes were proposed to investigate the effects of layered soft rocks. The results showed that the deformation of ribs was obviously larger than that of the roof and floor when the roadway passed through three types of strata.When the roadway was completely in a coal seam, the change of deformation in ribs was not obvious,while the deformation in the roof and floor increased obviously. These results can provide guidance for excavation and support design of roadways in layered soft rocks.