直墙拱形巷道围岩应力场分析

为得出直墙拱形巷道围岩应力分布规律,应用复变函数弹性理论推导了直墙拱形巷道围岩应力分布的解析表达式。对直墙拱形巷道边界的围岩应力和巷道水平线方向的围岩应力分布规律进行分析,并考虑直墙拱形巷道断面高宽比和侧压系数对其影响规律。研究表明：在不同巷道断面高宽比、侧压系数下,直墙拱形巷道围岩应力集中区域主要集中在直墙底部底角处、拱形顶板中点附近和底板中部3个位置。不同巷道断面高宽比下,直墙拱形巷道沿水平线的应力分布规律基本相同。侧压系数大于1时,采用巷道断面高宽比小于1较有利于巷道稳定;侧压系数小于等于1时,采用巷道断面高宽比大于1较有利于巷道稳定。     

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。     

高地应力巷道断面形状优化数值模拟研究

选取矩形、直墙半圆拱形、马蹄形、三心拱形、圆形和椭圆形6种巷道断面形状开展优化研究.采用FLAC5.0数值模拟软件研究了几种典型断面在岩体中开挖后巷道围岩塑性区分布、围岩主应力差分布和围岩变形特征,分析了不同侧压系数λ对它们的影响,在此基础上提出了巷道支护"等效开挖"的理念和"无效加固区"的概念.断面形状对高地应力巷道围岩主应力差分布影响不大,但等效开挖半径决定围岩塑性区分布,无效加固区越大,在巷道周边产生变形就越大,反之亦然.高应力巷道应根据λ的大小和主应力方向选择合理断面形状是圆形或椭圆形.     

三心拱形巷道调节风窗面积计算公式的误差分析和校正

本文对调节风窗面积计算公式进行了分析。实验研究证明，利用现有理论调节风窗面积计算公式求算调节风窗面积时误差较大，而误差与巷道的几何形状等因素有关。当利用现有理论调节风窗面积计算公式求算梯形巷道调节风窗面积时的误差比三心拱形巷道时的误差大，根据实验研究结果，提出了在三心拱形巷道安设调节风窗时的理论公式校正系数和校正公式。     

三心拱形巷道调节风窗面积计算公式的误差分析和校正

本文对调节风窗面积计算公式进行了分析。实验研究证明，利用现有理论调节风窗面积计算公式求算调节风窗面积时误差较大，而误差与巷道的几何形状等因素有关。当利用现有理论调节风窗面积计算公式求算梯形巷道调节风窗面积时的误差比三心拱形巷道时的误差大，根据实验研究结果，提出了在三心拱形巷道安设调节风窗时的理论公式校正系数和校正公式。     

巷道断面形状最佳选择的模糊决策

本文从巷道受力角度出发,利用模糊数学方法和国外新近提出的应力和均匀化理论,在巷道断面形状的优化比较方面,首次提出一种根据巷道周围平均应力集中系数MSCF来选择最佳断面形状的定量方法——模糊决策方法。应用此方法,作者结合某矿山深部地质、应力条件,确定该矿深部开采巷道的最佳形状为准椭圆形,为矿山深部开采设计提出了建议。     

白象山铁矿采矿进路断面形状优化

针对采矿进路易产生片帮、冒顶等破坏现象,采用FLAC3D深入揭示了三心拱形、切圆拱形与直墙拱形等3种断面形状采矿进路开挖后围岩塑性区和位移的变化规律,确定了合理断面为切圆拱形。并且针对切圆拱形断面拱高为0.5~3.0 m等6种尺寸进行优化设计,拱高的变化对顶板和底板的塑性范围影响较大,对帮部的塑性范围影响较小,且对顶板下沉影响较大。拱高为2.0 m时更有利于施工及采矿进路的长期稳定。     

深部“三软”煤层回采巷道断面优化研究

针对淮北矿区深部"三软"煤层工作面半圆拱梯形巷道超前支护工艺复杂的技术难题,以邹庄矿3204首采工作面的高产高效开采实际为背景,提出了利用"平顶+双圆弧"代替半圆拱的断面优化模式,开发了平顶U形巷道断面,运用理论分析、数值模拟并结合现场实测资料,研究了断面优化的理论基础并提出了优化高度的概念.结果表明:合理选择优化高度能够降低巷道围岩应力集中程度,提高"三软"巷道的整体稳定性及端头替棚效率;消除木垛架棚工艺并满足设备结构尺寸的优化高度h0应满足:0.9mh02.4m;断面优化高度的临界值为1.2m.     

分析粘弹围岩稳定性的新方法—离散记忆积分法

提出一种新的数值方法——离散记忆积分法。它用于分析粘弹围岩在弹性衬砌支护下的稳定性问题。文中Boltzmann＇s积分,即积分型粘弹本构关系,在总的时间和空间上被离散,而在离散的每个时步内使用以微分型本构关系为基础的对应性原理。方法不受巷道断面形状和衬砌建成时间的限制,可求出围岩和衬砌内的应力、位移及两者交界面上的围岩压力,通过将圆形断面巷道的计算结果与解析解比较,证明本方法是有效的,并对直壁圆拱形巷道进行了数值分析。     

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.     

Numerical analysis of the effects of rock bolts on stress redistribution around a roadway

Besides opening geometry, in situ stress and material properties, opening support also has significant effects on stress redistribution around a roadway. To investigate these effects of rock bolts on the stress redistribution around a roadway, a series of numerical studies were carried out using the finite difference method. Since the stress changes around a roadway caused by rock bolting is small relative to the in situ stress, they cannot obviously be observed in stress contour plots. To overcome this difficulty, a new result processing methodology was developed using the contouring program Surfer. With this methodology, the effects of rock bolts on stress redistribution can obviously be analyzed. Numerical results show that in the three patterns of rock bolts installed in the roof, in the roof and the two lateral sides, and in all the four sides of the rectangular roadway, the maximum stress magnitude of the increase is 0.931 MPa, 2.46 MPa,and 6.5 MPa, respectively; the bolt number of 5 can form an integrated ground arch; the appropriate length and pre-tensioned force of the rock bolt is 2.0 m and 60 k N, respectively. What is more, the ground arch action under the function of rock bolting is able to be effectively examined. The rock bolts dramatically increase the minor principal stress around a roadway which results in significant increase in material strength. Consequently, the major principal stress that the material can carry will greatly increase.With adequate supports, an integrated ground arch which is critical for the stability of roadway will be formed around the roadway.     

锚固体强度与组合拱承载能力的研究与应用

通过模拟试验证明了锚固力的作用在于提高巷道周边破裂围岩的残余强度,并使锚固体形成组合拱．研究了锚固组合拱承载能力的理论计算问题并应用于工程实践,有效地控制了软岩巷道围岩．     

古汉山矿东大巷“钢棚+注浆”支护工程实践

针对焦作矿区古汉山矿东大巷围岩属高应力、节理化、强膨胀的极软岩特性,采用一次拱形钢棚支护、二次锚注支护的"钢棚+注浆"支护技术方法,有效控制了巷道的强烈变形,避免了巷道维修,取得了软岩支护的最佳效益.     

钢筋混凝土低矮抗震墙性能研究及有限元分析

模拟试验了7片不开洞低矮抗震墙和4片开洞低矮抗震墙,编制了钢筋混凝土有限元全过程分析程序,研究了单调加载及低周反复荷载作用下低矮抗震墙的力-变形性能,揭示了其应力分布、裂缝产生和发展的规律以及周边框架的约束机理等。根据低矮墙的受力机理提出了抗震墙的强度和刚度实用计算公式。     

跨采条件下采场底板巷道参数的优化设计

根据底板应力场的作用特征,研究了采场底板巷道跨采作用下的合理层位、法向距离、平面位置等技术参数对巷道稳定性的影响,提供了有关跨采技术参数优化设计的方法及其结果．     

基于损伤本构关系的高拱坝安全度评价方法

基于损伤本构关系的非线性有限元能较为精确地模拟拱坝的实际工作性态,主要依据大坝的变形和应力分布及大小、损伤破坏情况等对坝体安全进行评价.但也存在一些问题,如以建基面相对损伤面积作为控制指标时,要先确定建基面的容许损伤范围.在介绍了损伤本构关系的基础上,提出了以大坝整体刚度不改变为基准的建基面容许相对损伤面积确定方法,为损伤本构关系用于高拱坝安全度评价的控制标准提供了一个新的思路,并以溪洛渡高拱坝为例进行了计算.     

Floor heave in the west wing track haulage roadway of the Tingnan Coal Mine: Mechanism and control

Floor heave of a roadway is a dynamic phenomenon that often happens in the roadways of coal mines. It seriously affects safe production in the coal mine. Floor heave has long been one of the most difficult problems to be resolved during coal mining. An analysis of floor heave in the soft rock surrounding the roadway, and the factors influencing it, allowed the deformation mechanism in the west wing double track haulage roadway of the Tingnan Coal Mine to be deduced. Three types of floor heave are observed there: intumescent floor heave, extrusion and mobility floor heave, and compound floor heave. Control measures are proposed that have been adopted during a recent repair engineering project. Control of the floor heave in the west wing track haulage roadway was demonstrated. The reliability and rationality of a combined support technology including floor anchors, an inverted arch, and anchoring of both sides was verified by mine pressure data and the field observations. Waterproofing measures were also undertaken to assist in the control of floor heave.     

Support technology for mine roadways in extreme weakly cemented strata and its application简

For the engineering geology conditions of bad mine roadway roof and floor lithology in extremely weak cemented strata, the best section shape of the roadway is determined from the study of tunnel surrounding rock displacement, plastic zone and stress distribution in rectangular, circle arch and arch wall sections, respectively. Based on the mining depth and thickness of the coal seam, roadway support technology solutions with different buried depth and thickness of coal seam are proposed. Support schemes are amended and optimized in time through monitoring data of the deformation of roadway, roof separation, I-beam bracket, bolt and anchor cable force to ensure the long-term stability and security of the roadway surrounding rock and support structure. The monitoring results show that mine roadway support schemes for different buried depth and section can be adapted to the characteristics of ground pressure and deformation of the surrounding rock in different depth well, effectively control the roadway surrounding rock deformation and the floor heave and guarantee the safety of construction and basic stability of surrounding rock and support structure.     

高精度非线性平面应力单元的研究与应用

采用共旋坐标法导出了四边形平面应力单元在大转动、小应变条件下的几何非线性和材料非线性的单元切线刚度矩阵,在此基础上编制相应的有限元程序;对有解析解的例题计算表明,提出的共旋坐标法四边形平面应力单元的列式、程序具有较强的非线性分析能力;还对单跨石拱桥进行了受力全过程分析,计算结果提供了对小跨度石拱桥非线性性能的更多的了解,可供工程设计人员参考。     

考虑土体自重应力场的拱效计算方法

抗滑桩是用于加固边坡,防止边坡滑移失稳的主要措施,土拱体易在桩间形成.本文将桩间土拱简化为水平拱,并假定处于平面应变状态,在考虑土体自重应力场前提下,对桩侧摩阻力为拱座的拱体计算方法进行了研究,揭示了土体的自重应力场对桩土拱体的量化影响.研究结果表明：自重应力场的存在对桩间土拱效应起着明显的加强作用,不考虑土体的自重应力场,也就是把土体看成是无重介质,进行桩土拱体模式的设计过于安全.