Study on Distribution Characteristics of Mining Stress and Elastic Energy Under Hard and Thick Igneous Rocks

In the coal measure strata, igneous rocks are often invaded, and their occurrence, size, and distribution form play an important role in mining safety. The breakage of hard and thick igneous rocks easily induces dynamic disasters, such as rock burst, mine seismicity, gas outburst, and surface subsidence, which seriously threaten mine safety production. In view of the working face with overlying hard and thick igneous rocks, the evolution characteristics of mining stress and energy distribution under hard and thick igneous rocks were investigated. Furthermore, the influence law of different horizons and thicknesses of igneous rock on overlying strata movement law, stress distribution, and energy distribution was analyzed based on FLAC3D numerical simulation. Results show that no evident subsidence of the overlying strata exists before the igneous rock is broken. Additionally, the subsidence amount of the overburden is suddenly increased after the igneous rock is broken, thereby showing significant mutability. Before the igneous rock breaks, a high stress area is formed around the goaf, and the stress concentration gradually increases with the increase of the mining scope. After the igneous rock breaks, the coal under high stress is prone to induce dynamic disasters under the action of strong dynamic load. However, the advanced abutment pressure and stored energy rapidly decreased. The accuracy of the numerical simulation is verified by field monitoring. Results of the study are of considerable significance for safe mining of working face under similar geological conditions.     

煤矿井下硬岩定向钻进PDC钻头选型及试验分析

为了提高煤矿井下硬岩定向钻进的效率,在分析硬岩定向钻进PDC钻头的结构要求的基础上,选择了3种不同类型的PDC钻头进行煤矿井下硬岩定向钻进试验。试验结果表明,平底型PDC钻头不适用于定向钻进硬岩,而三翼抛物线型钻头和四翼平角型钻头在定向钻进硬岩时,表现出长寿命、高效率等特点,适合于定向钻进硬岩地层,大大提高了煤矿井下定向钻进硬岩地层的效率。     

地基不均匀沉降对上部结构影响的三维弹性支承分析法

地基不均匀沉降是导致建筑工程事故的主要原因之一。为了研究地基不均匀沉降对上部结构内力、变形、周期等影响,提出了将地基(或基础)模拟为三维弹性支座的有限元分析方法,将上部结构和地基基础进行整体分析。以深圳市少年宫“水晶石”大厅结构为例,运用有限元软件ANSYS,将三维弹性支承分析法与常用的固定支座法和竖向弹性支承分析法进行了对比分析,验证了三维弹性支承分析法的合理性,从而得出了一些有益的结论,可供设计人员参考。     

煤矿采空区场地地基稳定性及适宜性分析

结合一煤矿采空区场地作为新建高层住宅小区场地,通过开采条件、地表移动变形综合确定煤矿采空区的稳定性;采用工程类比法、采空区特征判别法、活化影响因素分析法、地表剩余变形判别法等判别采空区场地工程建设适宜性;建议采空区场地采取吸收地表沉陷变形的柔性措施和抵抗地表沉陷变形的刚性措施来确保拟建建筑物的安全.     

模糊信息优化处理方法在采空区地表移动变形预计中的应用

将模糊信息优化处理方法应用到采空区地表移动变形预计下沉系数的求取中.选取深厚比、普氏系数和煤层倾角三个因素,通过信息扩散,模糊近似推论,分别建立各指标与下沉系数的模糊关系,得到模糊关系矩阵,最后使用实际资料对其进行验证.预测结果与实际资料符合程度较高.该方法清晰、易用,得出的精度较高,能使更多的影响因素参与评判.其中评价因素的选取较为关键,要与实际相结合.     

大直径软岩嵌岩桩端阻发挥性状实测分析

通过对工程试桩资料的分析,阐述桩端支承条件不同时端阻力发挥性状的差异.结果表明:当桩底支承强时,端阻发挥较为缓慢;桩底支承弱时,端阻增加较为迅速,两试桩的破坏均以过大的沉降作为标志;当荷载达极限时,端阻增加幅度都出现陡降.     

近红外光谱仪测定岩石中蚀变矿物方法研究

基于岩石中蚀变矿物对近红外光谱的吸收原理,确定测量蚀变矿物最佳波长范围,采用数学和谱图学习方法对岩石中蚀变矿物进行定性和定量分析。通过蚀变矿物特征光谱,提取光谱参数,建立蚀变矿物与成矿关系模型。以采自福建紫金山矿区钻孔岩芯测量结果为例,说明近红外蚀变矿物分析法的可靠性,并得出结论。     

恒温下含硫酸钠盐粗颗粒土盐胀特征及过程研究

通过恒温条件下粗颗粒土盐胀试验，对粗颗粒土盐胀特性进行了分析和讨论，试验结果表明，粗颗粒土不具有强烈盐胀特性，然而，粗颗粒土体一旦形成硫酸钠盐聚集层后，遇外来水分、会发生突发的破坏性盐胀，造成建筑物的破坏。     

Failure Effect of Seismic Faults and the Slope Stability Along Highways Under Seismic Hazards Based on Dynamic Finite Element Analysis and Genetic Algorithm

Geotechnical and Geological Engineering - In order to investigate the failure effect of seismic fault and the slope stability under seismic damages along highways, the spatial distributions of...     

碳酸盐岩中有机质组成特征分析

对碳酸盐岩有机质组分进行分类时，有两种分类标准，一是主要采用煤岩学方法，二是采用孢粉学研究方法。本文使用煤岩学方法作为标准，对碳酸盐岩有机质的组成特征进行分析。按有机质来源和有机组分光性和形态等方面差别划分为内源有机质、次生有机质和陆源有机质三类。内源有机质类中分腐泥组和动物有机组，前者主要来源于菌藻类，后者则主要来源于浮游动物有机体；次生有机质中区分出微粒体、有机包裹体、沥青；陆源有机质类分类术语仍沿用煤显微组分分类系统和术语。碳酸盐岩烃源岩的有机质主要为腐泥型，有机质来源以低等藻类为主，且有机质组成特征与碳酸盐岩烃源岩的地质年代有关。碳酸盐岩还存在着差异演化的特征。     

选频法在南阳宏发煤矿老窑水勘探中的应用

探讨选频法在煤矿老窑水勘探中的应用,以南阳宏发煤矿部分采空区及采空充水区为例,运用选频法,探测地下煤矿采空区及采空充水区位置。通过瞬变电磁法验证,选频法解释成果准确可靠。该资料可以说明选频法在寻找、确定煤矿采空充水区具有良好的效果。     

Applicability Research on the Dip Slope with Interbeddings of Weak and Strong Rocks Using Strength Reduction Method

Based on the combination of FLAC^3D software and strength reduction method, the applicability of three kinds of instability criterion of the stability of dip slopes with interbeddings of weak and hard rocks is studied. Then the failure process, failure mode and stability of the slopes are analyzed. The results show that: (1) the maximum unbalance rate affects the final calculated results; there is no certain relation between the convergence of calculation and the slope stability. The convergence of the displacement curves of key points and the ultimate displacement values should also be concerned to determine the slope stability. The maximum unbalance rate and the amplitude of the reduction affect the determination of the characteristic point in the displacement curve. It is difficult to quantitatively evaluate the shear strain rate when judging the slope stability, the judgment is not convenient and the error is large. Combining with calculation convergence criterion and feature point displacement mutation criterion is helpful to improve the accuracy of judgment on the limit state of the slope. (2) Slope deformation and failure process can be roughly divided into four stages qualitatively; the rock mass has buckling failure can be divided into three stages according to the deformation characteristics. The potential shear export of slope with buckling failure locates above the slope toe. Different combinations of weak and strong rock thickness does not affect the failure mode of slope, which all bellows to buckling failure mode, but it will affect the slope stability coefficient; with the increase of the thickness of strong rock and weak rock, the stability coefficient increases. If the thickness of the strong rock increases, the stability coefficient increases as well when the thickness ratio is constant.     

Analysis of Concrete Piles Under Horizontal and Vertical Simultaneous Loading with P-Y Method and Finite Element Analysis

Geotechnical and Geological Engineering - Pile foundations are often exposed to vertical and lateral loads. In common pile analysis, it is assumed that the effect of these two load types do not...     

基于误差方程常数项的变权迭代法在核电测量中的运用

测量平差处理过程中对大量的观测数据进行误差性质的有效实时甄别,尽量减少误差较大的观测值对最终成果质量的显著影响,在测量数据处理中具有重要的意义。结合核电平面控制测量特点,给出了判别方向、距离观测异常值阀值的简易计算方法,可以对异常观测值进行有效探测;指出在求解待定点未知参数前对异常值进行动态定权,可以保证最终观测成果质量不受异常值的显著影响,相对稳健估计利用验后观测值残差动态定权,可以提高数据处理效率及质量。     

Effects of Cyclic Loading on the Shear Behaviour of Infilled Rock Joints Under Constant Normal Stiffness Conditions

The variation of the shear strength of infilled rock joints under cyclic loading and constant normal stiffness conditions is studied. To simulate the joints, triangular asperities inclined at angles of 9.5° and 18.5° to the shear movement were cast using high-strength gypsum plaster and infilled with clayey sand. These joints were sheared cyclically under constant normal stiffness conditions. It was found that, for a particular normal stiffness, the shear strength is a function of the initial normal stress, initial asperity angle, joint surface friction angle, infill thickness, infill friction angle, loading direction and number of loading cycles. Based on the experimental results, a mathematical model is proposed to evaluate the shear strength of infilled rock joints in cyclic loading conditions. The proposed model takes into consideration different initial asperity angles, initial normal stresses and ratios of infill thickness to asperity height.     

基于数值模拟的远程工程支持在海洋19-6井的实践

数字化和智能化是钻井工程发展的新方向,但目前仍处于初级阶段。针对海洋19-6井中下部井段存在异常压力层,预测钻井液安全窗口较窄的问题,通过Drillworks软件采用dc指数法和分段测井资料校正法开展了地层随钻压力监测、通过动态跟踪软件Well-Ahead软件结合Landmark软件水力模块校正开展了随钻动态水力（随钻ECD当量密度和起下钻抽汲和“激动”压力分析）监测,保证了井底和套管鞋钻井液循环当量在三压力安全窗口内。通过这种远程数据支持模式的建立,进一步推进了钻井工程数字化进程,有效保证钻井工程安全。     

Dynamic Study on Fracture Problems in Viscoelastic Sedimentary Rocks Using the Numerical Manifold Method

The viscoelastic deformation behavior of a sedimentary rock under different loading rates is numerically modeled and investigated by the numerical manifold method (NMM). By incorporating a modified 3-element viscoelastic constitutive mode in the NMM, crack initiation and propagation criteria, and crack identification and evolution techniques, the effects of the loading rates on the cracking behavior of a sedimentary rock, such as crack open displacement, crack sliding displacement, crack initiation, crack propagation and final failure mode, are successfully modeled. The numerical results reveal that under a high loading rate (>1,000 MPa/s), due to the viscoelastic property of the sedimentary rock, not only the structural behavior deviates from that of elastic model, but also different cracking processes and final failure modes are obtained.