江西临川地区相山铀矿田构造应力场分析

相山铀矿田是中国最大的、与火成岩有关的中低温热液型矿床,断裂构造控矿特征明显。目前该矿床的后备资源出现危机,因此开展矿田构造研究,为深部及其外围找矿提供科学指导迫在眉睫。在野外观测分析和节理、擦痕实地测量的基础上,利用构造解析法、共轭剪节理分析法、断层擦痕反演模拟法及X光岩组法等,通过吴氏网投图分析和计算机的反演计算,确定了相山铀矿田多期次构造活动的变形特征及其主应力方向;并根据构造变形叠加关系及其成岩时代的确定,推断了应力作用的期次和时代。为此,将相山铀矿田的构造应力场划分为3期6个阶段,包括：成矿前的基底变形和早期火山活动阶段,早期矿化蚀变和第一、第二主成矿阶段,及其成矿期后阶段,矿体局部被错断;并深入分析了不同阶段构造活动及其铀成矿特征,探讨了区域构造应力场的演变与铀成矿作用关系,认为两者具有一致性特征,进而指出了区域富大矿体产出的有利构造部位。     

龙门山断裂带测区古构造残余应力随深度分布及带中残余能量

以岩体正交异性弹性理论为基础，用Ｘ射线法，在龙门山断裂带测区，选取３个小区深钻孔系列的岩心，测量了岩体中宏观残余应力场的水平和铅直三维主分量、水平和铅直最大剪应力，及其应变能密度随深度的分布，分析了它们沿深度的分布规律，估算了该断裂带岩体中储存的宏观残余弹性应变能的量级     

Focal mechanism inversion in the Giudicarie–Lessini seismotectonic region (Southern Alps, Italy): Insights on tectonic stress and strain

A set of 41 focal mechanisms (1989–2006) from P-wave first polarities is computed from relocated seismic events in the Giudicarie–Lessini region (Southern Alps). Estimated hypocentral depths vary from 3.1 to 20.8 km, for duration magnitudes (M_D) in the range 2.7–5.1. Stress and strain inversions are performed for two seismotectonic zones, namely G (Giudicarie) and L (Lessini). This subdivision is supported by geological evidence, seismicity distribution, and focal mechanism types. The available number of data (16 in G, 22 in L) does not make possible any further subdivisions. Seismotectonic zones G and L are undergoing different kinematic regimes: thrust with strike-slip component in G, and strike-slip in L. Principal stress and strain axes in each sub-region show similar orientations. The direction of maximum horizontal compressive stress is roughly perpendicular to the thrust fronts along the Giudicarie Belt in zone G, and compatible with right-lateral strike-slip reactivation of the faults belonging to the Schio-Vicenza system in zone L. On the whole, kinematic regimes and horizontal stress orientations show a good fit with other stress data from focal mechanisms and breakouts and with geodetic strain rate axes.     

海南东北部地区地壳地震各向异性特征初步研究

基于海南省地震台网2000~2013年的区域地震波形数据,用剪切波分裂系统分析方法(SAM)获得了海南琼东北部地区"九五"数字台网中2个台站的剪切波分裂参数。结果表明,快剪切波偏振优势方向代表了原地最大主压应力方向。七星岭台NE方向的快剪切波偏振优势方向与区域水平主压应力场方向不一致,与NE走向的断裂一致,体现了局部构造和局部应力场的复杂性;青山岭NNE向的快剪切波偏振优势方向揭示了NNE走向断裂的构造意义。同时,本研究证实,位于活动断裂上或几条活动断裂交汇部位的台站的快剪切波偏振优势方向与对所选用的小地震起控制作用的活动断裂走向一致,而快剪切波偏振优势方向较为离散则反映了该区域复杂的断裂构造和应力分布特征。     

某深埋长隧地应力演化及围岩应力位移模拟研究

结合西部地区某深埋长大公路隧道信息化施工,对深埋长隧地应力演化及围岩应力位移进行了弹塑性有限元数值模拟研究.研究结果表明,隧道轴线现代地应力状况与隧道埋深、地层岩性及构造发育程度有关,最大地应力为40.0MPa左右;隧道周边围岩应力在曲边墙底部最大,约38.0MPa,隧道开挖引起的围岩应力影响范围约25.0m;隧道水平收敛和拱顶下沉位移与隧道埋深近于成直线关系.这些研究结果为深埋长隧信息化设计和施工以及围岩稳定性分析提供了科学依据.     

超高沥青混凝土心墙高应力水平的降低措施研究

随着沥青混凝土心墙堆石坝的快速发展,超高沥青混凝土心墙堆石坝建设迎来了前所未有的机遇,但随着坝高的增加,心墙的安全挑战也变得异常突出。基于应力水平的定义,提出降低超高沥青混凝土心墙高应力水平的措施,依托心墙应力水平的敏感性研究,推算了独立满足和综合满足心墙屈服剪切破坏控制标准的心墙材料强度参数(最敏感材料参数)取值范围。研究表明,心墙应力水平随坝高和河谷岸坡坡比的增加而显著增大;心墙破坏比R_f、黏聚力c和内摩擦角φ属于高敏感性参数;增大心墙破坏比R_f、黏聚力c和内摩擦角φ,能够显著地降低心墙应力水平;推荐适宜建设超高沥青混凝土心墙堆石坝的心墙破坏比R_f、黏聚力c和内摩擦角φ取值范围:R_f≥0.8、c≥0.4MPa和φ≥31.5°(坝高h=200 m),且随坝高的增长梯度按5%/25 m、15%/25 m和5%/25 m进行调整。     

Is Ziarat a Potential Site for Conventional or Unconventional Energy Resources?

A structural interpretation of the Ziarat block in the Balochistan region (a part of the Suleiman Fold and Thrust Belt) has been carried out using seismic and seismological data. Seismic data consists of nine 2.5D pre‐stack migrated seismic lines, whereas the seismological data covers the Fault Plane Solution and source parameters. Structural interpretation describes two broad fault sets of fore and back thrusts in the study area that have resulted in the development of pop‐up structures, accountable for the structural traps and seismicity pattern in terms of seismic hazard. Seismic interpretation includes time and depth contour maps of the Dungan Formation and Ranikot group, while seismological interpretation includes Fault Plane Solution, that is correlated with a geological and structural map of the area for the interpretation of the nature of the subsurface faults. Principal stresses are also estimated for the Ranikot group and Dungan Formation. In order to calculate anisotropic elastic properties, the parameters of the rock strength of the formations are first determined from seismic data, along with the dominant stresses (vertical, minimum horizontal, and maximum horizontal). The differential ratio of the maximum and minimum horizontal stresses is obtained to indicate optimal zones for hydraulic fracturing, and to assess the potential for geothermal energy reservoir prospect generation. The stress maps indicate high values towards the deeper part of the horizon, and low towards the shallower part, attributed to the lithological and structural variation in the area. Outcomes of structural interpretation indicate a good correlation of structure and tectonics from both seismological and seismic methods.     

车载修井机井架静强度有限元分析

车载修井机井架静强度分析中,通常略去绷绳和风载的影响,这与井架的实际工况不符。以ABAQUS软件为工具,对某车载修井机井架进行了有限元分析。在不同的静钩载及风载作用下,得出了井架所能承受的最大静钩载以及确定了井架薄弱点所处的位置。并通过计算合理地缩短了绷绳的斜拉范围。     

基于梯度塑性理论的岩样在压剪条件下变形及稳定性分析

考虑了正应力及剪应力联合作用在岩样的端部,而且,在正应力被视为变量,剪应力被视为常量这一特殊条件下,对剪切带的变形特征及剪切带-带外弹性体系统的失稳判据进行了分析.根据剪切虎克定律及梯度塑性理论,提出了剪切带内部弹性应变、塑性应变及总应变的解析式,对上述三种应变进行积分,提出了剪切带错动弹性位移、塑性位移及总位移的解析式.利用压缩虎克定律及几何关系建立了剪切带外弹性体的刚度的表达式.根据刚度理论,建立了剪切带-带外弹性体系统的失稳判据.考虑岩样端面的剪切应力后,在流动剪切应力相同时,剪切带内部的弹性剪切应变(均匀分布)将增加;剪切带内部的塑性剪切应变(不均匀分布)将减小;剪切带的弹性剪切位移(线性分布)将增加;剪切带的塑性剪切位移(非线性分布)将减小;剪切带错动位移要小一些.另外,剪切应力对剪切带-带外弹性体系统的失稳判据没有影响.失稳判据仅和岩石的本构参数、剪切带倾角及结构尺寸有关.     

井水位气压效率b值动态响应的断层-前兆场主应力组合模式

统计鲁03，04井流水作业闰的气压效率b值发现，在华北及其周缘绝大多数地震前两井前兆异常形态各异，经分析井孔定位断层走向与地震前兆场主应力的组合模式不同是产生上述现象的根本原因。