富水砂卵石地层地铁联络横通道人工冻结数值分析

人工地层冻结法作为一种常用的土层加固方法,被广泛应用于煤矿、地铁等地下结构工程中。成都地区的砂卵石地层含水量丰富,渗透系数大,实施冻结法难度更大。以成都地铁10号线某隧道区间为工程依托,研究采用人工冻结法在砂卵石地层中修建联络横通道的问题。对冻结工程进行现场监测,根据冻结管实际布置形式建立考虑冰水相变的非线性三维弹塑性热—力耦合数值模型,通过现场监测和数值模拟两种手段对积极冻结期温度场和位移场的发展及分布规律进行研究。结果表明：数值模拟结果与现场监测数据吻合较好,建立的数值模型比较可靠;冻结壁交圈时间是冻胀变形快速增长的临界时间点,交圈时间约为25 d;冻结43.7 d时冻结壁厚度达到2 m,在37.8 d时冻结壁内平均温度达到-10 ℃,满足后续开挖施工要求。     

水平地层冻结法在上海地铁修复工程中的应用

上海地铁四号线修复工程中采用水平冻结法进行修复段隧道和已建完好隧道之间的暗挖贯通施工,取得圆满成功。利用基于“一线总线”的冻结法温度监测系统进行现场实时监测。并依据监测数据,判别了冻结管是否漏盐水以及完好隧道段冻土壁的封水效果,得出了冻土壁温度场形成规律,计算出积极冻结期结束时间,分析了各施工工序对冻土墙温度影响。分析结果表明,温度是判断冻土壁特征的重要指标。通过合理布置温度监测点,采用信息化温度监测手段,掌握冻结壁发展的规律,可确保冻结法施工安全。     

淮南顾桥矿东风井人工冻土力学性能试验分析

淮南顾桥煤矿东风井采用冻结法施工,为了提供表土层冻结参数以进行矿井设计,本文对风井井筒孔检查孔所取土样进行了人工冻结的单轴抗压强度、冻胀性能以及结冰温度试验研究,得到了其应力-应变、冻胀力和结冰温度等参数,试验结果为淮南类似矿井建设提供了设计基础.     

润扬大桥南锚碇基坑排桩冻结法的物理模拟试验研究

文章采用物理模拟的方法来研究冻胀力。根据相似理论的基本原理,建立了大型室内模拟试验系统,探明冻结壁温度场分布规律、冻结壁扩展规律、多种工况下排桩承受的水平冻胀力状况、卸压孔对水平冻胀力的释放效果、排桩应力、各道腰梁的水平位移、支撑内力和基坑开挖过程的稳定性等,为验证数值计算结果,对动态设计及信息化施工提供了必要的技术参数和科学依据。     

朝阳矿主副井冻结基岩段深孔减冲光爆法掘进和整体钢模板砌壁设计与施工

朝阳矿主、副井冻结基岩采用3 3m深孔减冲光爆法施工,冻结段外层钢筋混凝土井壁平均掘砌速度分别达104 2m/月和106m/月,为爆破界探索出了前所未有的实践成果,给出了冻结壁、冻结管爆破安全和冻结段整体钢模板高度的理论计算.     

朝阳矿主副井冻结基岩段深孔减冲光爆法掘进和整体钢模板砌壁设计与施工

朝阳矿主、副井冻结基岩采用3.3m深孔减冲光爆法施工,冻结段外层钢筋混凝土井壁平均掘砌速度分别达104.2m/月和106m/月,为爆破界探索出了前所未有的实践成果,给出了冻结壁、冻结管爆破安全和冻结段整体钢模板高度的理论计算.     

冻结壁弹塑性反演分析

本文简要介绍了冻结壁稳定性的研究范围及方法,并初次用位移反分析法结合冻结壁模型试验、对冻结壁稳定性问题进行了综合研究。最后作者提出了用极限应变作为冻土工程稳定性判据的新观点。     

宁夏红四矿人工冻土力学特性试验研究

为了研究西部冻结岩土的物理力学性质以指导矿井建设,对宁夏红四矿副井井筒检查孔所取土样进行了人工冻结的单轴抗压强度和蠕变试验,得到了其应力——应变和蠕变规律,为西部类似矿井建设,提供了设计基础.     

深厚粘土层冻结管受力机理模拟分析

针对杨村煤矿副井407．3m～445．35m段特厚砂质粘土层冻结管断裂情况,本文利用有限元软件ABAQUS进行受力机理模拟分析,得到冻结管应力、位移分布规律,从而判断出冻结管断裂位置在砂质粘土与砂土交界处,通过与现场监测情况进行对比,分析出冻结管受力断裂主要原因在于两种土层冻胀不同造成的,并提出相关施工建议为后期矿井建设提供参考。     

深厚表土层立井冻结壁稳定性上限分析

在深厚表土层中采用冻结法建井时,冻结壁的稳定性是影响立井工作面和外层井壁安全的重要因素。本文在考虑深厚表土层中水平地压、混凝土水化热和冻结壁材料属性等因素影响下,采用极限分析中的上限定理建立冻结壁破坏模型,分析冻结壁在不同破坏模式下冻结压力上限值的变化范围及对立井空帮和外层井壁的影响,研究不同角度、不同深度下冻结壁破坏范围及对井壁的影响,并将计算结果与现场实测结果进行对比分析。结果表明,深厚表土层中冻结壁变形造成的冻结压力远大于通过重液公式计算得到的水平地压,随着埋深增加,不仅冻结压力显著增大,而且在冻结壁变形范围扩大时冻结压力增速加快。计算得到冻结壁不同破坏模式下的冻结压力上限值,与实测结果比较,推测出可能的冻结壁变形破坏程度,这有利于指导工程实际。     

Mechanical performance of a double-face reinforced retaining wall in an area disturbed by mining

The application of a double-face reinforced retaining wall during road construction can reduce engineering costs, speed road paving and have a good influence on environment. An ABAQUS numerical model of a double-face reinforced retaining wall was built. The influence of surface subsidence induced by mining was considered. A physical model test was also performed in the laboratory on a reinforced retaining wall. The influence of subsidence induced by mining was observed. The numerical results match measurements in the laboratory very well. The vertical pressure on the base of the retaining wall, the horizontal displacement of the wall and the horizontal soil pressure acting on the wall were analyzed. The differential settlement of the reinforced belt and axial forces in the wall were also studied.     

兖州矿区立井井壁破裂的原因分析及防治

针对兖州矿区有８ 个生产井筒发生井壁破裂事故的问题,在进行调查、治理和分析近期监测资料的基础上,详细研究了本区井壁破裂的原因,认为由于第四系下组水位的强烈疏降引起砂层压缩所产生的垂向附加应力与井壁自重应力之和大于井壁混凝土的强度是导致井壁破裂的最根本原因,提出了可以用ｅ－ｐ 曲线法、ｐｗ －ｆｎ 法和模糊聚类评判法预测井筒的稳定性,同时提出了井筒破坏的防治措施．     

寺河矿井安全高效采煤方法的选择与分析

介绍了寺河矿井东区煤层开采技术条件 ,对综采放顶煤采煤法和大采高采煤法两种方案进行了论证比较 ,通过采煤实践数据证明 ,得出大采高采煤法是适合寺河矿井安全高效采煤方法的结论     

露天煤矿端帮残煤开采及边坡暴露时间分析

为了提高露天开采的煤炭资源回收率，掌控露天煤矿端帮残煤开采工程安排，提出了水平和近水平大型露天煤矿汽车运输内排条件下，露天煤矿端帮露井联采、端帮陡帮开采、减少露天煤矿端帮边坡暴露时间的措施．结果表明：采掘工作帮帮坡角越大、内排土场工作帮帮坡角越大、工作线推进强度越大、内排土场下部水平排土台阶高度越大、采场坑底宽度越小露天煤矿端帮边坡的暴露时间越短；当露天煤矿端帮实行陡帮开采时，汽车运输内排通路可设在采场中部回填搭建。     

高大型采场全尾砂充填挡墙可靠性的力学分析

冬瓜山铜矿床埋藏距地表深达1000m,矿区构造应力复杂,属高地应力分布区域,采用大空场嗣后全尾砂胶结充填法开采．按充填料浆3种不同力学性质状态对充填挡墙进行了受力分析和计算,指出了影响充填挡墙可靠性的因素并提出了首采地段8#采场充填挡墙实施方案．     

安家岭露天煤矿端帮采煤方法研究

将井工开采的放顶煤采煤技术应用于平朔安家岭露天煤矿端帮煤开采,提出了“煤墙支撑简易放顶煤”采煤法。该法将煤层全厚分为上下两个采掘层,每个采掘层又分为上下两个分层,采掘下分层时用单体液压支架支护,采掘上分层时采用顶板放炮民落煤,采掘的煤层厚度可达10m以上,此种采煤方法具有安全可靠,资源回收率高、作业效率高等优点。     

Mechanics of rib spalling of high coal walls under fully-mechanized mining

In order tO solve the problem of rib spalling of high coal walls in fully-mechanized (HCWFM) mines, we used the principle of damage mechanics to analyze coal wall rib spalling. The results show that coal wall rib spalling is, to a certain degree, a macro-performance of the development of micro-cracks. We built a mechanical model to simulate the damage to the front of coal walls, carried out theoretical calculations of the damage parameters, analyzed the effect of mining height, original cracks, seam strength, horizontal stress, vertical displacement of the coal walls and other parameters on coal wall rib spalling,which conform well with the results of our field measurements and numerical simulation. The key to control coal wall rib spalling is to control the development of cracks in coal walls. Accelerating the speed of advancing the working face, improving the setting load of support and the horizontal force of the guard board, strengthening coal walls and other technical measures can effectively reduce the degree of damage to the coal walls and control coal wall rib spalling at HCWFMVl faces.     

Pore pressure fluctuations of overlying aquifer during residual coal mining and water-soil stress coupling analysis

Three test models and a simulation model were constructed based on the prevailing conditions of the Taiping coalmine in order to analyze pore pressure fluctuations of an overlying aquifer during residual coal mining. As well, the relation between pore pressure and soil stress was evaluated. The model tests show the vibrations of pore pressure and soil stress as a result of mining activities. The simulation model tells of the response characteristics of pore pressure after mining and its distribution in the sand aquifer. The comparative analysis reveals that pore pressure and soil stress vibration are activated by unexpected events occurring in mines, such as collapsing roofs. An increased pore pressure zone always lies above the wall in front or behind the working face of a mine. Both pore pressure and vertical stress result in increasing and decreasing processes during movements of the working face of a mine. The vibration of pore pressure always precedes soil stress in the same area and ends with a sharp decline. Changes in pore pressure of sand aquifer are limited to the area of stress changes. Obvious changes are largely located in a very small frame over the mining face.     

厚冲积层疏水引起地面沉降时井筒受力分析

首先分析临涣矿区井筒破裂的原因，进一步分析厚冲积层疏降水引起地面沉降情况下井筒附加纵向载荷的产生及其计算方法．在上述分析基础上，根据矿区现有井筒技术参数和实际状态，按照摩擦阻力为直线分布与三角形分布两种形式，应用第四强度理论推算摩擦阻力极限值大小，此值可作为本矿区以及地质条件类似矿区的现有井筒井壁强度验算与新井井壁设计的重要参考．     

Systematic principles of surrounding rock control in longwall mining within thick coal seams

Effective surrounding rock control is a prerequisite for realizing safe mining in underground coal mines.In the past three decades, longwall top-coal caving mining(LTCC) and single pass large height longwall mining(SPLL) found expanded usage in extracting thick coal seams in China. The two mining methods lead to large void space left behind the working face, which increases the difficulty in ground control.Longwall face failure is a common problem in both LTCC and SPLL mining. Such failure is conventionally attributed to low strength and high fracture intensity of the coal seam. However, the stiffness of main components included in the surrounding rock system also greatly influences longwall face stability.Correspondingly, surrounding rock system is developed for LTCC and SPLL faces in this paper. The conditions for simultaneous balance of roof structure and longwall face are put forward by taking the stiffness of coal seam, roof strata and hydraulic support into account. The safety factor of the longwall face is defined as the ratio between the ultimate bearing capacity and actual load imposed on the coal wall.The influences provided by coal strength, coal stiffness, roof stiffness, and hydraulic support stiffness,as well as the movement of roof structure are analyzed. Finally, the key elements dominating longwall face stability are identified for improving surrounding rock control effectiveness in LTCC and SPLL faces.