Numerical evaluation of bearing capacity of a foundation in strain softening soil

The problem involving soil mass supported by a retaining wall and subjected to the load exerted by a rigid footing is considered. The collapse load of the system is determined using progressively more advanced plasticity formulations. It is demonstrated that the estimates based on elastoperfect plasticity differ very substantially from those obtained by admitting locally unstable strain softening response.     

Research on geomagnetic tectonic characteristics of the crust in Haicheng seismic area

In this paper, the two metnods, rectangular spectrum (RS) and maximum entropy power spectrum (MES), have been used in calculating the geomagnetic structures of the crust in Haicheng and its adjacent areas and carrying out the geomagnetic stratification of the crust. The result of the research indicates that the crust can be devided into such three layers as nonmagnetic layer, magnetic layer and regressive magnetic layer from the top to the bottom. It is also found the distribution of the geomagnetic bottom interface (Curie surface) is consistent with the lower interface of the upper crust and the top interface of the middle crust of the velocity structure of the crust. It is very interesting that the Haicheng earthquake of Feb. 4, 1975,M 7.3 occurred at the depth gradient belt of the Curie isotherm surface. So, to research on the geomagnetic layers and the distribution characteristics of the Curie isotherm surface is meaningful in judging potential seismic foci. The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 448–454, 1993. The data of velocity and electricity materials used in this paper are as reference from the related materials of the maps and directions etc. of Donggou-Haicheng-Dong Ujimqin Qi Geoscience Transect by Prof. Zao-Xun LU, Huai-Kuan XIA and others.     

几种岛状硅酸盐矿物的形貌学研究

测量研究了锆石、黄石、石榴石、羟硅铍石和符山石的形态和微形貌，并分别列出了这些晶体的化学成分和其它鉴定参数，观察到的生长和溶蚀螺纹证实螺旋生长机制在硅酸盐矿物晶体生长中具有重要意义。     

面向对象的数据模型及其应用

本文从结构数据模型和语义数据模型的特点和关系出发,引出面向对象的数据模型(OODM)的基本概念,重点讨论了由Abiteboul和Hull提出的IFO模型,对该模型在GIS空间数据库设计中的应用进行了初步探讨,最后指出了OODM的具体实现途径。     

新构造运动对阿尔泰山及萨吾尔山山前带地下水的控制

虽山前带第四系很薄,但由于新构造运动掀斜作用及断裂的贯通作用,构造盆地第三系含水层与山前带地下水产生水力联系并获得很高的压力水头.山前带第四系厚度小的原因,是中更新世以后上升幅度增大,早中更新世沉积遭受强烈剥蚀.由于第四系很薄,曾长期被人认为地下水贫乏.但据勘探证实,较大冲积扇有丰富的潜水资源.     

余震序列分维特征的初步探讨

本文应用关联维数计算方法,分别计算了雷波5.4级地震、康定5.2级、5.8级地震和大邑6 1/4级地震的余震序列的关联维数D_2,并给出了相应的离差和相关系数。它们的关联维数分别为2.26982、1.93915、2.28738和1.5367。在这4个地震序列中,发生强余震的序列的D_2大于无强余震的序列。     

Slip-weakening instability on a strike-slip fault with asperity

In this paper, we studied the slip-weakening instability on a finite and vertical strike-slip fault with asperity. We assumed that the fault strength is uniform in depth, but it is non-uniform in the strike direction, i.e., there is an asperity on the fault. The segments of the fault with and without asperity follow the same type of constitutive law, but the peak stresses are different. The material surrounding the fault is represented by elastic plates whose upper-surface and bottom are stress-free. We use finite element method to study the evolution of theoretical displacement, stress and strain fields that vary with a remote displacement. Here the displacement and frictional stress are not given in advance, but are determined in the solving process. According to the results, we compared the theoretical displacemeut and the distribution of frictional stress on the fault between the stable and unstable slips. In addition, we compared the results in this paper with known results for the strike-slip fault with a segment of lower strength.     

青海南部高寒草地土壤冻融交替期水热特征分析

为进一步了解高寒草地土壤冻融交替过程及其对水热因子的响应机制,通过2014年8月1日至2015年8月1日不同土层土壤温度和水分观测资料的对比分析,较为系统地探讨了青南高寒草地土壤冻融期不同深度土层土壤温度和水分的变化特征。结果表明,青南高寒草地土壤冻融阶段大体可分为初冻期、稳定冻结中期、稳定冻结后期和消融期4个时期;不同土层土壤温度随气温的变化呈周期性波动,且随着土层的加深变幅减小;不同冻融期表层和亚表层土壤温度和水分波动幅度较大,下层土壤对水热因子的敏感性较小;土壤完全冻结的天数达44~115d,日冻融交替过程主要发生在表层和亚表层土壤。土壤冻融交替增强了土壤的保水性,对该区草地植被提前返青和初级生产力的提高具有促进作用。     

长白山现代理论雪线和古雪线高度

根据冰川地貌和地形特征、岩性、冰川沉积物的风化程度以及OSL测年结果,认为长白山地区发育两期冰川作用,即末次冰盛期和晚冰期,测年结果分别为20.0±2.1ka和11.3±1.2ka。根据平衡线（ELA）处6～8月多年平均气温（T）和年降水量（P）的关系,计算长白山现代理论雪线高度为3380±100m。通过积累区面积比率AAR（accumulation-arearatio）、冰川末端到山顶高度TSAM（the terminal to summit altitudinal）,冰川末端至分水岭平均高度Hofer（the terminal to average elevation of the catchment area）、末端至冰斗后壁比率THAR（toe-to headwall altitude ratios）、冰斗底部高程CF（cirque-floor altitudes method）、侧碛堤最大高度法MELM（maximum elevation of lateral moraines）等方法计算该区末次冰盛期雪线高度为2250～2383m,平均值2320±20m。考虑到末次冰盛期后地壳上升20m,当时雪线的实际高度为2300±20m,冰盛期的雪线降低值为10⁸0±100m。晚冰期北坡和西坡的雪线高度分别为2490m和2440m,平均值2465m,考虑新构造运动后的雪线实际高度2454m,降低值926±100m。长白山新构造运动（LGM上升约20m,晚冰期上升约11m）在末次冰盛期以来对冰川发育的影响不明显。