在三轴压缩下大理岩循环加载实验的初步研究

在围压10、50、100和200MPa,应变率5×10^-5/s和室温条件下,采用山东掖县大理岩岩样,在800t高温高压伺服三轴流变仪上进行了连续加载和循环加载实验.对岩样的残余强度和弹性模量的变化等问题进行了初步研究.得出:在低围压下（<100MPa）,残余强度与超过极限强度后的循环加载次数有关;超过极限强度后加载弹性模量随着非弹性应变的增加而减小,并趋于一个极限值.在高围压下（≥100MPa）,残余强度几乎与超过极限强度后的循环加载次数无关;超过极限强度或者产生应变强化后加载弹性模量几乎不随非弹性应变的增加而减小.     

地震预报中地电阻率高精度计算方法

本文利用回归分析、谐波分析和预测、理论研究了从大地电位差(Vsp)和人工电位差(ΔV)迭加的合成势差(E)中高精度分离ΔV的方法。实际计算表明:当Vsp变化规律较强时,该方法的精度比常规方法提高几倍至十几倍;当Vsp变化规律较弱时,该方法的精度一般高于或接近于常规方法的精度。     

延边闹枝破碎蚀变岩型金矿床研究

延边地区闹枝金矿为一破碎蚀变岩型金矿床,产于中生代火山盆地外缘的早海西期花岗闪长岩出露区,矿体严格受构造破碎带控制。本文从矿床产出的地质地球化学特征入手对区内岩浆岩与成矿的关系进行了系统研究,揭示出闹枝金矿与中生代火山杂岩有密切的成因联系.闹枝金矿为—燕山期钙碱性火山岩浆活动所形成的火山—次火山热液矿床.矿床形成于中温、pH值为弱酸—弱碱性、Eh值较低的弱还原—还原条件.成矿作用具有多阶段性。金主要以氯金络合物和硫金络合物形式迁移.     

突出小地震活动事件作为中强震短临预报判据的研究

对新疆1970年以来突出小震活动事件进行了统计分析,给出突出小地震活动事件与5级以上中强震的对应关系,提出以突出小地震活动事件中小地震发生的时间间隔和频度预报中强震的短期判据。     

Stress determination by back-analysis of excavation-induced stress changes — a case study

Summary An Underground Research Laboratory (URL) has been constructed by Atomic Energy of Canada Limited (AECL) to study various aspects of disposing of nuclear fuel waste in the Canadian Shield. In order to ensure good quality and long life of the construction, one important factor to be considered is the in situ stress field. As part of the research program, stress changes have been measured during the advance of a tunnel to monitor the stress response to excavation. It is desirable to estimate the state of in situ stress from these stress change measurements and to compare the results with overcoring data. This paper describes the application of a recently developed stress change fitting technique for stress determination. The basic principle and the fitting procedure are briefly summarized and the back-analysis process for the data collected at the URL is presented in detail. A boundary element model was used to predict the stress changes as required by the fitting approach. This new method of in situ stress determination was successfully applied in this case. The back-analyzed stresses agree very well with those determined from overcoring tests. The quality of individual measurements was assessed and the required minimum number of measurements for a conclusive data interpretation is evaluated.     

THE "CLIMATE TRANSITION" OF THE LONG TERM VARIATION OF OCEAN CONDITION IN THE NORTHERN PACIFIC AND RESPONSE OF ATMOSPHERIC CIRCULATION IN RECENT 50 YEARS

In this paper, the analysis of net volume of the Kuroshio in PN section of the East China Sea, the calculations of volume transports of the North Equatorial Current (NEC) and North Equatorial Countercurrent (NECC) and the upper layer heat content (0～150 m) in 137°E section during 1967-1992,and the sea surface temperature anomaly (SSTA) in the northern Pacific are illustrated. Meanwhile,the long term variation of subtropical high in northern hemisphere and in the western Pacific, and atmosphere oscillation are also analyzed. By using Mann-Kendall method, the verification shows that the ocean condition and atmospheric circulation system mentioned above all presented "climate transition"during the mid-and late-Stage of 1970's, that is, the volume transports of the Kuroshio, the NEC and the NECC varied from weak to strong; the SSTA changed from the type of La Nina to that of E1 Nino,which were coincident with atmospheric circulation system, i. e. the subtropical high in northern hemisphere and in the western Pacific, and atmospheric oscillation all had the feature of changing from weak to strong, which indicated the response of atmospheric "climate transition" to oceanic "climate transition ".