高围压下冻结砂土的强度特性   总被引：2，自引：6，他引：2  

马巍  吴紫汪 《冰川冻土》1996,18(3):268-272

在高围压条件下，对冻结兰州砂土在不同温度和不同应变速度下进行三轴压缩试验，试验结果表明，围压的增大和应变速度的减小明显增强了冻土的塑性性能；同时，随围压的增大，冻土的抗剪强度增加，但随围压的进一步增加，它出现降低的趋势，存在一个临界 围压，此临界围压值随温度的变化而变化，但不随应变速率而变化。  相似文献   

欠压实地层古地层压力恢复的统计模拟法及其在松辽盆地中的应用   总被引：1，自引：0，他引：1  

付广  庞雄奇  姜振学  张树林 《沉积学报》1996,(1)

恢复烃源岩古地层压力和对于研究其生留排烃过程具有重要意义。Ｎａｋａｙａｍａ［１］等在开展盆地模拟研究时应用Ｒｕｂｅｙ（１９５９）和Ｃｈａｐｍａｎ（１９７）等人提出的数学地质模型对欠压实地层的古地层压力进行恢复。本文通过对松辽盆地欠压实地层的研究发现欠压实因子随地层厚度、埋深、围岩渗透性等地质条件的不同而改变，在此基础上提出了欠压实地层压力恢复的统计模拟法，克服了目前Ｎａｋａｙａｍａ［１］等将地层埋藏过程中的欠压实因子视为常数的不足，从而使计算结果更接近实际。统计模拟法在松辽盆地的应用结果表明了这一方法在实用中的可行性和有效性。  相似文献   

南海北部大陆架西段地热条件与油气资源前景          下载免费PDF全文

汪缉安  李雨梁 《地质科学》1996,31(4):416-428

北部湾盆地下第三系由于油源母质特性原因和适于生油的空间相对局限,总体上看,天然气的潜力大于石油。生油岩与地温条件在空间上的配置适当决定了珠三盆地油气资源的良好前景。较高的地温与古地温环境是莺琼盆地成为南海北部大陆架天然气富集区的重要条件,较高的地温不仅使盆地中西部上第三系烃源岩能够广泛生气,也是本区有巨大远景的深成高压气(盆地中、西部)与浅成生化成因气的形成与富集的重要条件。  相似文献   

An effective approach to determine the dynamic source parameters     

Xiaofei Chen  Keiiti Aki 《Pure and Applied Geophysics》1996,146(3-4):689-696

In this study, we present a new and effective method to determine the dynamic source parameters (i.e., stress drop and strength distribution). We first assume that the kinematic source parameters, i.e., the slip and rupture time distributions on the fault plane, are known from the previous source inversion studies. Then, using the seismic source representation theorem we determine the dynamic stress field on a fault plane from known kinematic parameters. Finally, we determine the strength of the fault defined as the peak stress just before the rupture. We have tested the validity of this method by using an illustrative two-dimensional analytical example. To assess the applicability of this method, we have applied it to study the 1979 Imperial Valley earthquake, and obtained consistent results with those ofMiyatake's (1992) andQuin's (1990). Compared with previous methods, this new method is simple, straightforward and accurate, and needs much less calculation. Therefore, it is expected to be useful in exploring the seismic source process.  相似文献   

中国南方风化磷块岩研究   总被引：3，自引：2，他引：3  

李铁生  文素秋 《化工矿产地质》1996,18(3):196-200

中国南方风化磷块岩中的风化磷矿的自然类型可分为两类七种型式，其中以“原位面型风化磷矿”和“位移溶洞砂砾磷矿”为主。风化磷矿是由其原矿的自身特性与外部适宜条件（水文地质条件为主导）综合作用的产物。根据碳酸盐、磷酸盐矿物分解、淋失程度可划分为弱风化、风化、强风化三个阶段。可用直接法、间接法和数学法３类共１３种方法加以判别  相似文献   

赤峰—朝阳地区金矿成矿物理化学条件研究     

刘纲 《黄金地质》1996,2(4):43-49

系统论述了区内各大类金矿的成矿温度，成矿压力，各种气体的逸度、ｐＨ值，金离子及其配合物的活度，讨论了金的迁移形式，推测了区内各类矿液中金的沉淀机制。  相似文献   

伊舒断裂带南、北段震源参数研究          下载免费PDF全文

董瑞树  刘志平 《地震地质》1996,18(1):59-65

利用时间城小地震地震图的方法，研究了震源参数与介质特性的差异。据初步研究结果，伊通－舒兰断裂南、北两段的震源应力降与Ｑ值存在差异。该方法是断层的震源深度范围内介质特性研究的补充，为断裂的分段提供一个重要方法  相似文献   

Cyclic strength and deformation of crushable carbonate sand     

Masayuki Hyodo  Noritaka Aramaki  Masayuki Itoh  Adrian F.L. Hyde 《Soil Dynamics and Earthquake Engineering》1996,15(5):331-336

Cyclic triaxial tests have been carried out on a skeletal carbonate sand from the west coast of Eire. Results are presented for undrained cyclic shear tests on samples with 80% of relative density consolidated under both isotropic and anisotropic conditions. Failure was defined as a 5% double amplitude cyclic strain and a 5% peak axial strain for stress-reversal and non-reversal stress conditions, respectively. Using this definition the cyclic strength for isotropically consolidated samples was affected by the confining pressure although the angular platey nature of the sand resulted in higher cyclic strengths than for a comparable silica sand. For anisotropically consolidated samples the cyclic strength increased with increasing initial static shear stress while on the other hand the cyclic strength normalised in the usual way with respect to the initial confining pressure decreased as this pressure increased.  相似文献   

Modifications of the dispersion relations for surface waves in a layer on a half-space     

Oldřich Novotný  L. V. Burlako  T. A. Proskuryakova 《Studia Geophysica et Geodaetica》1996,40(2):167-177

Summary Dispersion relations for Love and Rayleigh waves in a layer on a half-space are modified by introducing quadratic slownesses instead of velocities. The advantages of this approach are demonstrated on analytical formulae for computing the group velocity.  相似文献   

Porewater pressure increases in soil and rock from underground chemical and nuclear explosions   总被引：3，自引：0，他引：3  

Wayne A. Charlie  George E. Veyera  Deanna S. Durnford  Donald O. Doehring 《Engineering Geology》1996,43(4):225-236

A review and analysis of chemical and nuclear explosive-induced porewater pressure increases and induced rise in groundwater table elevations (groundwater mounding) is presented. Our analysis indicates that residual pore pressure increases and groundwater mounding can be induced by underground chemical and nuclear explosions to scaled distances of 879 m/(kt)^1/3. This relationship is linear over seven orders of magnitude of explosive energy ranging from a 0.01 kg chemical explosion to a 100 kt nuclear explosion and is valid for a wide variety of saturated geological profiles. Underground chemical explosions, and probably underground nuclear explosions have the potential to induce liquefaction of water-saturated soils to scaled distances of about 260 m/(kt)^1/3.  相似文献