非均质细胞元随机分布对高温岩石介质中裂纹扩展影响的数值试验研究

在平面应变模型下,以花岗岩为样本,采用随机介质固热耦合数学模型及有限元方法进行了高温岩石介质中裂纹扩展影响的数值试验研究。在指数分布、韦泊分布2种随机分布和温度的作用下,研究了材料非均质性对岩石介质中裂纹扩展的影响,并对岩石热破裂做了详细研究,揭示了概率分布形式、分布参数.时间与花岗岩样本的热破裂过程的变化规律。

鄂尔多斯盆地下白垩统含水层储水岩石特征与介质结构研究

本文采用沉积学与水文地质学交叉研究的思路,对鄂尔多斯盆地下白垩统含水层储水岩石特征与含水介质结构进行了研究。下白垩统是由宜君-洛河、华池-环河、罗汉洞-泾川三套含水岩组组成的一个厚达1300m、具多层结构的巨型碎屑岩地下水系统,发育以长石砂岩、长石石英砂岩为主的多类型储水砂岩,其沉积形成于以河流、沙漠为主的多种陆相沉积环境。由于受沉积、成岩及后期剥蚀等作用的控制,各含水岩组储水岩石的类型、厚度及分布,以及储水空间的类型和发育程度、储水孔隙介质结构均有明显变化;在与其它水文地质条件的共同影响下,下白垩统地下水赋存和富集条件总体呈现"盆地北好南差、北部上好下差、南部下好上差"的宏观分布规律。

欧亚大陆及边缘海岩石圈的结构特性

欧亚大陆及其边缘海地区是由约30多块尺度不同、形成时代和性质各异的板块或地块拼合而成。这些岩石圈板块或地块经过长时间的漂移,多次聚合与分离,碰撞与增生,在新生代最后形成现代的拼合欧亚大陆。欧亚大陆及其边缘海的板块或地块可以分为以下六类:(1)前寒武纪巨型克拉通地块及地盾;(2)前寒武纪小型克拉通地块及板块;(3)显生宙造山带及汇聚地块;(4)陆陆碰撞型地块及造山带;(5)新生代边缘海海盆;(6)大陆裂谷盆地及增生地块。高分辨率地震面波层析成像,显示同一类型的板块或地块的岩石圈和软流圈的速度结构十分相似,呈现出其独有的速度分布特征。不同类型板块或地块的速度结构有重大差异。直到400km深度,各个板块和地块的横向差异才逐渐减小。一般而言,前寒武纪克拉通板块及地块的岩石圈巨厚具有高速性质、软流圈很薄或不存在;边缘海、造山带等区域岩石圈较薄和速度较低,软流圈发育。根据欧亚大陆及边缘海地区天然地震层析成像,人工地震剖面数据及其他有关资料,建立了欧亚大陆及其边缘海岩石圈模型。

调整炸药岩石匹配爆破试验研究

在研究过程中测量油母页岩岩石、岩体弹性纵波速度,确定选取炸药类型,采用BP神经网络和经典炸药岩石匹配理论相互论证炸药性能的数据调整方案、在相同爆破参数条件下进行油母页岩炸药和岩石匹配爆破试验,采用Split-Desktop软件分析试验后岩石块度分布以验证匹配效果。在试验后分析了油母页岩岩石块度分布,发现尾矿率升高,试验结果不理想。通过对爆破试验设计的分析,排除孔网参数、装药结构等的可能性;总结出岩体节理裂隙、节理面与自由面交角、爆破延期时间3方面原因。

东昆仑早石炭世火山岩的地球化学特征及其构造背景

东昆仑早石炭世火山岩主要沿昆中缝合带及其旁侧分布，岩性以玄武岩为主，之后亦有安山岩和英安岩产出，先后形成于洋脊、洋岛和岛弧构造环境。洋脊玄武岩Ｋ２Ｏ、Ｐ２Ｏ５、ＳｉＯ２、ＲＥＥ含量和ＦｅＯ／ＭｇＯ比值低，钙、铁、镁高，轻重稀土元素分馏差。岛弧玄武岩硅、碱、铝和ＲＥＥ含量以及ＬＲＥＥ／ＨＲＥＥ比值高，镁、铁质低。洋岛玄武岩ＴｉＯ２和Ｐ２Ｏ５高，Ｋ２Ｏ低，ＲＥＥ和ＬＲＥＥ／ＨＲＥＥ介于前二者之间。火山岩的构造背景表明，早石炭世昆中断裂带以“开”为主，形成洋脊玄武岩和洋岛玄武岩；早石炭世末转为“合”，形成岛弧型玄武岩、安山岩和英安岩。洋脊玄武岩的识别，对于研究区域构造及其演化甚为重要。

南极格罗夫山普通球粒陨石的化学-岩石类型分布及成对陨石的判别

中国第16次南极科考队在格罗夫山地区的蓝色冰表面上发现并回收了28块陨石,其中26块为普通球粒陨石.根据电子探针分析数据和岩石矿物学特征,对这些普通球粒陨石进行了化学-岩石类型的划分,包括6个非平衡型L群陨石(L3),6个平衡型H群陨石(3个H4,1个H5,2个H6),9个平衡型L群陨石(3个L4,1个L5,5个L6)和5个平衡型LL群陨石(2个LL4,3个LL5).进一步详细的岩石结构特征和矿物化学组成对比表明,格罗夫山28块普通球粒陨石(包括首次回收的2块)中有5对陨石可能分别属于相同降落事件的不同陨石碎块,即成对陨石.因此,格罗夫山已回收的全部32块陨石可能代表了27次不同的陨石降落事件,表明该地区存在某种陨石的迁移和富集机制,是一新的陨石富集区.格罗夫山陨石的化学-岩石类型分布和质量分布特征与南极其他区域的陨石有显著的差异,可能反映了格罗夫山地区陨石的来源或富集机制的特殊性,但需进一步的工作加以确认,并揭示其内在的原因和意义.

山东地区混凝土骨料的碱活性研究

对山东地区的混凝土用骨料的碱活性进行了调研分析,并在地质专家的配合下对全省的骨料进行取样,经过对骨料的碱活性测试分析,认为山东地区确实存在碱活性骨料,并分析了山东地区的碱骨料反应破坏的工程实例。

水星,让我瞧瞧你的脸

水星上的盆地这张水星彩色图片是由信使号探测器拍摄的。不过，这张图中的色彩并不是水星实际的颜色，在图中，不同的颜色代表的是水星表面不同种类的岩石分布情况。图中最大的一片亮黄色区域就是卡洛里斯盆地，

水利部等三部门:合力打赢滇桂黔石漠化片区脱贫攻坚战

据了解,滇桂黔石漠化集中连片特殊困难地区跨广西、贵州、云南三省区,国土总面积为22.8万平方公里,大部分地处云贵高原东南部及其与广西盆地过渡地带,南与越南接壤,属典型的高原山地构造地形,碳酸盐类岩石分布广,石漠化面积大,是世界上喀斯特地貌发育最典型的地区之一,集民族地区、革命老区和边境地区于一体,是国家在新一轮扶贫开发攻坚战主战场中少数民族人口最多的片区。

趣谈蛇纹岩

笔者对蛇纹岩情有独钟。从六十年代初到内蒙古参观、考察蛇纹岩开始,后来到中天山超基性岩带进行普查评价,然后参加西准噶尔铬铁矿会战……。最近又在江苏北部发现由超基性岩蚀变成的蛇纹岩体群。蛇纹岩是一种用途广泛的矿产资源,依据调查研究的资料以及收集有关资料,在此作一简介,以飨读者。

A Probabilistic View of Debris Flow

Most debris flows occur in valleys of area smaller than 50 km2. While associated with a valley, debris flow is by no means a full-valley event but originates from parts of the valley, i.e., the tributary sources. We propose that debris flow develops by extending from tributaries to the mainstream. The debris flow observed in the mainstream is the confluence of the tributary flows and the process of the confluence can be considered as a combination of the tributary elements. The frequency distribution of tributaries is found subject to the Weibull form (or its generalizations). And the same distribution form applies to the discharge of debris flow. Then the process of debris flow is related to the geometric structure of the valley. Moreover, viewed from a large scale of water system, all valleys are tributaries, which have been found to assume the same distribution. With each valley corresponding to a debris flow, the distribution can be taken as the frequency distribution of debris flow and therefore provides a quantitative description of the fact that debris flow is inclined to occur at valley of small size. Furthermore, different parameters appear in different regions, suggesting the regional differentials of debris flow potential. We can use the failure rate, instead of the size per se, to describe the risk of a valley of a given area. Finally we claim that the valleys of debris flow in different regions are in the similar episode of evolution.

Effect of pre-tensioned rock bolts on stress redistribution around a roadway—insight from numerical modeling

The importance of the pre-tensioned force of rock bolts has been recognized by more and more researchers. To investi- gate the effect of pre-tensioned rock bolts on stress redistribution around roadways, a numerical analysis was carried out using FLAC3D and a special post-process methodology, using surfer, is proposed to process the numerical simulation results. The results indicate that pre-tensioned rock bolts have a significant effect on stress redistribution around a roadway. In the roof, pre-tensioned rock bolts greatly increase vertical stress; as a result, the strength of the rock mass increased significantly which results in a greater capacity of bearing a large horizontal stress. The horizontal stress decreases in the upper section of the roof, indicating that pre-tensioned rock bolts significantly reduce the coefficient and the size of the region concentration of horizontal stress. At the lat- eral side, pre-tensioned rock bolts greatly increase the horizontal stress; therefore, the rock mass strength significantly increases which results also in a greater capacity of bearing a large vertical stress. The greater the size of pre-tensioned force, the larger the region of stress redistribution around a roadway is affected and the higher the size of the stress on the roadway surface the more the rock mass strength increases.

Study on damages constitutive model of rocks based on lognormal distribution

The damage constitutive relation of entire rock failure process was established using the theory of representative volume element obeying the Iognormal distribution law, and the integrated damages constitutive model of rock under triaxial compression was established. Comparing with triaxial compression test result, it shows that this model correctly reflects the relationship of stress-strain. At the same time, according to the principle of the rock fatigue failure that conforms to completely the static entire process curve, a new method of establishing cyclic fatigue damage evolution equation was discussed, this method form is simple and the physics significance is clear, it may join preferably the damage relations of the rock static entire process curve.

分形几何在岩土工程中的应用

分形几何主要研究自然界不确定性的因素。水电工程与岩石、土及混凝土材料紧密联系,而土与岩石中存在大量分布不规则的裂隙或孔隙,因此,分形理论用于研究岩土工程具有一定的价值。

Influence of abrasive hardness on erosion wear of abrasive air jets

To make clear the influence of abrasive hardness on the erosion effect,the erosion experiments of abrasive air jet with the same impact energy were carried out.The influence of abrasive hardness on the erosion effect is clarified by comparing the different erosion depths.The main conclusions are as follows.Under the same mass flow rate and mesh number,the abrasive with a higher density needs greater pressure irrespective of hardness.After erosion damage,the abrasive size exhibits a Weibull distribution.The shape parameterβand Weibull distribution function of four types of abrasives are derived by the least squares method;moreover,βis found to have a quadratic relation with abrasive hardness.The results of the erosion experiments show that abrasive hardness and erosion depth are quadratically related.By calculating the increase in surface energy after abrasive erosion crushing,it is found that abrasive hardness has a quadratic relation with surface energy and that the increases in erosion depth and surface energy consumption are basically identical.In conclusion,the effect is a soft abrasive impact when the ratio of abrasive hardness(Ha)to the material hardness(Hm)is<2.6,and it is a hard abrasive impact when Ha/Hm>3.

Plastic-Flow Waves (“Slow-Waves") and Seismic Activity in Central-Eastern Asia

The results inferred from experiments with analogue models carried out previously have shown that two types of plastic-flow waves, “fast-waves" and “slow-waves", are induced in the lower lithosphere (including the lower crust and lithospheric mantle) under driving at plate boundaries and both of them are viscous gravity waves formed by the superposition of major and subsidiary waves. The major waves are similar to solitary waves and the subsidiary waves are traveling waves. The plastic-flow waves in the lower lithosphere control seismic activities in the overlying seismogenic layer and result in the distribution of earthquakes along the wave-crest belts. “Fast-waves" propagated with velocities of orders of magnitude of 100～102km/a have been verified by wave-controlled earthquake migration, showing the “decade waves" and “century waves" with the average periods of 10.8 and 93.4 a, respectively, which originate from the Himalayan driving boundary. According to the recognition of the patterns of the belt-like distribution of strong earthquakes with M S≥7.0, it is indicated further in this paper that the “slow-waves" with velocities of orders of magnitude of 100～101 m/a also originated under compression from the Himalayan driving boundary. Strong earthquakes with M S≥7.0 are controlled mainly by subsidiary waves, because the major waves with a duration of up to 106 a for each disturbance cannot result in the accumulation of enough energy for strong earthquakes due to the relaxation of the upper crust. The subsidiary waves propagate with an average wave length of 445 km, velocities of 0.81～2.80 m/a and periods of 0.16～0.55 Ma. The wave-generating time at the Himalayan driving boundary is about 1.34～4.59 Ma before present for the “slow-waves", corresponding to the stage from the Mid Pliocene to the Mid Early-Pleistocene and being identical with one of the major tectonic episodes of the Himalayan tectonic movement. It is shown from the recognition of the wave-controlled belts of strong earthquakes that two optimal patterns of wave-crest belts originated simultaneously from the eastern and western segments of the Himalayan arc, respectively. The overlap of wave-crest belts of these two systems is responsible for the relative concentration of energy and forms the seismic-energy-background zones for strong earthquakes with M S≥7.0.

Permeability in Flysch-Distribution Decrease with Depth and Grout Curtains Under Dams

A considerable number of in situ permeability tests in flysch are processed to a depth of 120m with a good spatial distribution. The distribution of permeability values for the different litho-types of this formation, their comparison and their decrease with depth is discussed. The depth where a permeability of 3 to 5×10-7m/sec can be retained (the limit of a reasonable grouting under a high dam) may be twofold if the geological history of the formation could not contain a compressional tectonic process. This depth may reach 100m in some cases. The differences in the mean values of permeability among the various litho-types are minor, while the presence of siltstones, always present although with varied participation, dramatically controls the global permeability.

Redistribution and magnitude of stresses around horse shoe and circular excavations opened in anisotropic rock

In this paper numerical analysis of underground structures, taking account the transverse isotropy system of rocks, was done using CAST 3M code by varying the shape of excavation and the coefficient of earth pressure k. Numerical results reveal that the anisotropy behavior, the shape of hole and the coefficient of earth pressure k have significant influence to the mining induced stress field and rock deformations which directly control the stability of underground excavation design. The magnitude of horizontal stress obtained for the horse shoe shape excavation(25.2 MPa for k = 1; 52.7 MPa for k = 2)is lower than the magnitude obtained for circular hole(26.4 MPa for k = 1; 59.5 MPa for k = 2).Therefore, we have concluded that the horse shoe shape offers the best stability and the best design for engineer. The anisotropy system presented by rock mass can also influence the redistribution of stresses around hole opened. Numerical results have revealed that the magnitude of redistribution of horizontal stresses obtained for transverse isotropic rock(12.1 MPa for k = 0.5; 25.2 MPa for k = 1 and52.7 MPa for k = 2) is less than those obtained in the case of isotropic rock(27.6 MPa for k = 1;48.6 MPa for k = 2 and 90.81 MPa for k = 2). The more the rock has the anisotropic behavior, the more the mass of rock around the tunnel is stable.

Modeling of Rocks with Spatial Distributed Fractures by Random Medium Theory

By using the spectrum expanding theory of random processes and Hudson's crack model,we developed a random medium model for rocks with spatial random distributed number density of cracks. This model could connect the micro-parameters of the cracks with the macro- mechanical properties, and can be effectively applied to model the real inhomogeneous medium. Numerical example indicates that the random distribution characters could be different for different elastic constants under the same random distribution of number density of cracks. By changing the value of the autocorrelation length pair, it is possible to model the difference of the distribution in the two coordinate directions. Numerical modeling results for seismic wave propagating in rocks with random distributed fractures using a staggered high-order finite-difference (SHOFD) are also presented.

银川市红墩子矿区钻孔亚粘土数据kriging插值方法比较研究

利用银川市红墩子矿区钻孔亚粘土数据,在ArcGIS支持下,使用四种克里金插值方法对亚粘土分布高程进行预测。采用交叉验证对插值精度进行评价时,根据最优条件对五参数进行线性相加作为判断预测误差大小的辅助工具,并综合插值结果的统计特征和分布图,得到如下结论:(1)针对本次研究数据,使用协同克里金插值方法,半变异函数模型为高斯函数,步长为8插值效果最好。(2)无论哪种插值方法,使用高斯半变异函数模型都是最优的。(3)交叉验证时将五个参数根据最优条件进行线性相加,能够在一定程度上反映预测误差好坏。(4)在研究数据较少,但它与其他数据存在较大相关性时可以使用协同克里金法,会在较大程度上提高插值精度。