Formation Depth of Coesite-Bearing Eclogite, Dabie UHPM Zone, China     

Lü Guxian 《中国地质大学学报(英文版)》2004,15(2):206-215

The plastic deformation of garnet in coesite-bearing eclogite,quartz eclogite and garnet amphibolite of the UHPM complex in Yingshan County in the Dabie Mountains has been studied. The stress generated by the strong tectonic movement was an important component of the total pressure that resulted in the formation of the eclogite in the Dabie UHPM zone. The three-dimensional tectonic principal stresses and additional tectonic stress-induced hydrostatic pressure ［ps=(σ1 σ2 σ3)/3］ are reconstructed according to the differential stress and the strain ratio(α) of the garnet in the minor coesite-bearing eclogite of the Yingshan County. Then the gravity-induced hydrostatic pressure(pg) is calculated following the equation p minus ps,where p is estimated to be 2.8 Gpa based on the quartz-coesite geobarmeter. Therefore,the thickness of the rock column overlying the coesite-bearing eclogite in the Ying-shan County is determined ≥32 km. This estimation,significantly different from ≥100 km,the previous one obtained solely based on the weight/specific weight ratio(W/SW),offers a proper explanation for the puzzle that no tracer of the addition of mantle-derived material has been found in the Dabie UHPM zone during the process of UHPM,although a number of researchers claim that this process took place at the depth of the mantle(≥100 km). It is concluded that attention should be paid to the additional tectonic stress-induced hydrostatic pressure in the study of UHPM zones.  相似文献   

P.ecent progress in studies of experimental rock mechanics and tectonophysics in China   总被引：1，自引：0，他引：1  

马胜利  马瑾 《地震学报(英文版)》2003,16(5):561-567

This paper reviews the recent progress in the studies of experimental rock mechanics and tectonophysics concern-ing seismology and physics of the Earth‘s interior in China. The progress is presented in the following aspects: a) A lot of results of experiment and numerical simulation enrich our knowledge of the brittle fracturing process under the condition with heterogeneity in material and structure; b) Some new results on frictional behavior of non-homogeneous faults reveal the complexity of faulting behavior; c) Some new results on the brittle-plastic tran-sition and plastic flow are obtained; especially the important progress is obtained on theological properties of rocks in the lower crust and the upper mantle; d) A lot of experimental results are obtained on rock physics at high tem-perature and pressure and have been used in study of material composition and state. These results provide useful information for understanding the physical properties and deformation mechanisms of material of the Earth‘s inte-rior and earthquake physics.  相似文献   

硬玉塑性变形的AFM特征   总被引：2，自引：0，他引：2  

郭颖  赖兴运 《矿物学报》2003,23(2):158-162

利用原子力显微镜(AFM)对缅甸硬玉进行表面观察，研究其纳米级范围内矿物晶体的超显微结构及构造特征，探讨其形成的动态过程和物理化学等外部条件。结果发现在缅甸硬玉表面存在大量残余变形现象，尤其是以典型的扭折带、亚晶粒、晶粒扭曲结构为特征，反映了硬玉晶体内聚集了大量的位错。这些现象表明硬玉在其结晶之后曾在高压及较高温的地壳深处经历了强烈的塑性变形过程，它们与地表或近地表低温、低压条件下形成的以脆性破裂为主的变形方式有本质的差别。硬玉中大量的塑性变形现象表明了它是在比较复杂的动态地质环境中形成的，深部的这种复杂变形作用使得缅甸硬玉有别于世界上其它地方的硬玉，其独特的地质形成过程造就了本区为世界上典型的也是最大的翡翠矿床。  相似文献   

磷酸盐缓凝剂的优选与水泥复合浆液性能研究   总被引：3，自引：0，他引：3  

阮文军  靖向党等 《地质与勘探》2002,38(4):83-86

研制了一种以无机聚合物（水玻璃）为速凝剂，以磷酸盐为缓凝剂配制而成的CWP水泥复合浆液。在该复合浆液中，用磷酸二氢铵作缓凝剂效果最好。CWP复合浆液在流变性，塑性强度，稳定性和结石强度上具有优良的性能。  相似文献   

四川巴中市南龛斜坡变形破坏机制分析与稳定性评价   总被引：2，自引：0，他引：2  

许向宁  李天斌  熊顺聪 《地质灾害与环境保护》2002,13(3):27-31

在研究南龛斜坡自然地质环境条件、岩土物理力学参数以及现场勘探测试的基础上，采用地质分析、半定量的弹塑性有限元分析、定量的极限平衡法分析、因素敏感性分析以及可靠性分析等方法，分析了斜坡的成因机制和稳定性，并计算了其破坏概率。作者们认为该斜坡变形破坏的地质力学模式为溜滑－蠕滑－拉裂型；坡面上雨水入渗是斜坡溜、蠕滑、拉裂变形破坏的主导诱发因素。计算结果表明就整体而言，斜坡无论在天然和饱水状态都处于基本稳定状态，宏观上斜坡还不具备大规模滑动的条件；但在饱水状态下，局部地段特别是斜坡前缘坡体将处于不稳定或潜在不稳定状态。  相似文献   

碎石桩复合地基承载力性状分析   总被引：2，自引：0，他引：2  

周建安 《地质灾害与环境保护》2002,13(3):73-78

按等置换率原则建立碎石桩复合地基有限元计算模型，在考虑基础刚度、荷载强度变化条件下对比分析了天然地基与复合地基附加应力分布特征、塑性区扩展规律；根据有限元计算结果分析了桩身荷载传递规律并与实测结果对比确定桩身应力随桩身呈指数衰减。计算结果还表明：桩土应力比不仅与桩土模量比有关，也与荷载水平及置换率有关；在鼓胀破坏情形下桩体侧向变形性质取决于桩周土而与置换率、模量比、桩长无关。  相似文献   

Wavelet‐based characterization of design ground motions     

Sushovan Mukherjee  Vinay K. Gupta 《地震工程与结构动力学》2002,31(5):1173-1190

With the recent emergence of wavelet‐based procedures for stochastic analyses of linear and non‐linear structural systems subjected to earthquake ground motions, it has become necessary that seismic ground motion processes are characterized through statistical functionals of wavelet coefficients. While direct characterization in terms of earthquake and site parameters may have to wait for a few more years due to the complexity of the problem, this study attempts such characterization through commonly available Fourier and response spectra for design earthquake motions. Two approaches have been proposed for obtaining the spectrum‐compatible wavelet functionals, one for input Fourier spectrum and another for input response spectrum, such that the total number of input data points are 30–35% of those required for a time‐history analysis. The proposed methods provide for simulating ‘desired non‐stationary characteristics’ consistent with those in a recorded accelerogram. Numerical studies have been performed to illustrate the proposed approaches. Further, the wavelet functionals compatible with a USNRC spectrum in the case of 35 recorded motions of similar strong motion durations have been used to obtain the strength reduction factor spectra for elasto‐plastic oscillators and to show that about ±20% variation may be assumed from mean to 5 and 95% confidence levels due to uncertainty in the non‐stationary characteristics of the ground motion process. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

中天山卡瓦布拉克一带古地壳层圈结构特征     

郭华春  董富荣  吴玉门  曹福根 《新疆地质》2002,20(4):352-356

中天山卡瓦布拉克一带，受长期掀斜隆升剥蚀，显示古地壳具层圈结构，盖层为火山岩，由于剥蚀局部残留，上地壳由劈理带和结晶片岩带组成；中地壳为塑性流变层，由板状韧流带和环状重熔岩带构成；下地壳仅见呈热隆上升的环状中基性杂岩性。板状韧流带具大型韧性剪切变形特征，中基性杂岩为下地壳热隆岩浆上升，并使中地壳岩石形成重熔型花岗岩，共同构成环状杂岩体。该地壳层圈结构形成于新疆古大陆震旦－寒武纪裂解及准噶尔洋盆发育过程中。  相似文献   

同构造花岗岩的一种显微构造标记   总被引：5，自引：0，他引：5  

谢才富 《岩石矿物学杂志》2002,21(2):179-185

在许多同构造花岗岩中，发现一种不同于糜棱基质的微细粒矿物集合体－－微粒交生体，充填于大粒级矿物的三结点和接合缝内，体积分数一般为2％－6％，由微粒石英、斜长石、钾长石、蠕状石等组成，成分上与花岗质岩浆的晚期结晶产物相当。根据其产状、成分、岩相学特征及有关实验资料，认为它是较强应力作用下岩石所含少量残余熔体（质量分数约小于3％－5％）的结晶产物，可作为岩体同构造侵位结晶的显微构造标志。  相似文献   

基于GF-1与Sentinel-2融合数据的地膜识别方法研究     

罗琪  刘晓龙  史正涛  屈冉  赵文智 《地理与地理信息科学》2021,37(1):39-46

随着我国地膜使用面积的增加和人们对土壤微塑料污染问题的日益关注,大尺度的地膜遥感识别已成为农业生产管理、土壤污染防治的必要手段。针对地膜光谱反射特征的复杂性以及基于单一遥感影像光谱特征识别方法错分率高等问题,该文以河北省邯郸市邱县为试验区,利用GF-1数据的空间细节与Sentinel-2数据的光谱信息进行NN Diffuse Pan Sharpening融合,据此建立地膜识别的特征矩阵(NDVI、MNDWI、NDBI、IBI、PSI),基于该特征矩阵可实现自动阈值地膜分层分类识别。多种方法的地膜识别结果精度对比表明:多源光学遥感数据融合方法的总体精度为94.87%,Kappa系数达0.89,显著优于基于单一数据源的深度学习法的精度(93.14%)以及基于传统机器学习分类方法的支持向量机(85.91%)和随机森林分类法(86.78%)的精度;通过与Sentinel-2多光谱影像融合,弥补了GF-1数据光谱分辨率低的缺陷,实现了多源数据在地膜识别中的优势互补,可为相关部门农业规划与管理以及生态环境保护等研究提供大尺度、高精度的地膜分布参考数据。  相似文献