裂隙岩体渗流与应力耦合的试验研究

通过对较大尺寸的裂隙岩体试块进行不同侧压力和加载条件下的渗流试验结果研究，分析了裂隙岩体渗流与应力的耦合机理，得出了不同应力条件下裂隙岩体渗流量与应力成四次方的关系。并且得出并非压应力都引起裂隙岩体的渗流量减小，当裂隙岩体受平行于裂隙面方向的单向压应力时，渗流量随着压应力的增加而增加。     

流体地质作用的构造效应

许多事实证明，在地壳及地球深部存在着大量的流体，它们以气体、液体、熔融体等形式存在于地球内部不同深度处。这些流体的活动在地壳及岩石圈运动演化过程中扮演着十分重要的角色，其作用贯穿于地壳与岩石圈运动演化的全过程，地球表面形成的各种构造与流体作用的参与有着密切的联系。     

松江河电厂小山水电站导流洞出口边坡稳定性分析

小山水电站导流洞出口边坡其地质结构为下部中侏罗世安山岩（αＪ２），其上覆盖了第三纪末第四纪初的玄武岩（βＮ～Ｑ），两者间为不整合接触，不整合面夹有０．１～０．６ｍ厚的粘土状及碎石粘土状夹层，产状倾向河床，倾角±２５°。在上覆玄武岩层中见有高倾角的宽张裂隙带，与不整合面一起构成松动岩体，不整合面为底滑面。通过边界条件的分析和稳定计算，松动岩体的抗滑系数Ｋ＝３．１０２，边坡是稳定的。在施工过程中采取了相应的安全保护措施，导流洞出口提前２８ｍ进洞，节约挖方量６００００ｍ３，提前了工期。经三年多的施工到运行，边坡无异常变化，表明该项优化设计是可行的。     

山谷冰川稳定态时积累区面积比率研究

探讨山谷冰川稳定状态时积累区面积比率，即ＡＡＲ值的大小，认为冰川物质平衡高程分布，平面形态及坡面坡度沿程变化形式是影响山谷冰川稳定态ＡＡＲ值的主要因素，并 山谷冰川稳定态ＡＡＲ值与物质平衡高程分布及平面形态之间的定量关系。山谷冰川适合于应用ＡＲ值法来研究古冰川的零平衡线高程。     

蚀变岩中物质迁移的定量计算：以锡矿山锑矿床为例

本文提出了确定沉积岩蚀变作用过程中的不活动组分的方法，并以锡矿山锑矿床为例，定量计算了蚀变岩中各组分的带入带出量，研究表明：锡矿山锑矿硅化过程中ＴｉＯ２和Ａｌ２Ｏ３为不活动组；ＳｉＯ２，Ｋ２Ｏ，Ｎａ２Ｏ及锑，硫，坤，汞，铅和钡为带入组分；而ＣａＯ，ＭｇＯ，Ｆｅ２Ｏ３，ＭｎＯ及铜，锌为带出组分，锑，钡，硫，ＳｉＯ２和ＣａＯ有较大的带进或带出量，锡矿山锑矿床矿石矿物为单一辉锑矿可能是由于矿液中缺少其它     

土体各向异性的再认识

土体原生和次生各向异性有本质不同。从柔度矩阵的角度分析了弹性和弹塑性理论对各向异性的反映 ;复杂应力状态下砂土真三轴试验结果表明 ,次生各向异性对土体应力应变关系有很大影响 ,是土体特性的本质体现 ,在土工数值分析中应当充分考虑其影响。     

K–Ar geochronology of the temporal change of eruptive style in the eastern Izu peninsula, central Japan

Abstract   A recent K–Ar study elucidated that eruptive style in the eastern Izu peninsula changed from polygenetic to monogenetic volcano at 0.3–0.2 Ma. To narrow down the time of change, we determined 10 K–Ar ages on Togasayama Andesite of Amagi volcano, the youngest polygenetic volcano in the area, and Togasayama Monogenetic Volcano, one of the oldest monogenetic volcanoes in the area, which overlies a part of the Togasayama Andesite. Dating results showed that the Togasayama Andesite effused at least from 0.34 to 0.20 Ma, whereas the Togasayama Monogenetic Volcano erupted at 0.26–0.29 Ma, suggesting that the northern part of the Togasayama Andesite effused after the eruption of the Togasayama Monogenetic Volcano. Considering previous data, it is therefore inferred that change of eruptive style in the eastern Izu area occurred during the period 0.29–0.20 Ma, with considerable overlap of both polygenetic and monogenetic volcanism.     

An experimental study on seismic responses of multifunctional vibration‐absorption reinforced concrete megaframe structures

Two models are tested on a shake‐table. One of the models is a normal reinforced concrete megaframe structure and the other is a multifunctional vibration‐absorption reinforced concrete megaframe structure in which the laminated rubber bearings are placed between the major frame and the minor frames. Two earthquake motions (the El Centro wave and the Taft wave) are used during the test. This paper presents the dynamic characteristic, the seismic responses and the failure mechanism of these two models under varying peak acceleration levels for each of the earthquake motions. The test results demonstrate that the aseismic behavior of a multifunctional vibration‐absorption reinforced concrete megaframe structure is much better than that of a normal reinforced concrete megaframe structure. Copyright © 2003 John Wiley & Sons, Ltd.     

Seismic structural control using an electric servomotor active mass driver system

This study investigates an electric‐type active mass driver (AMD) system for structural vibration control. Composed primarily of an electric servomotor and a ball screw, the electrical AMD system is free from noise problems, oil leakage, and labor‐intensive maintenance that commonly are associated with hydraulic AMD systems. The desired stroke amplification of the mass and the power demand of the servomotor can be adjusted via the ball screw pitch, which in turn affects the effectiveness and efficiency of the system. Meanwhile, an instantaneous optimal direct output feedback control algorithm is adopted. Numerical simulation is performed using a five‐story steel frame as the object structure under the conditions of the 1940 El Centro earthquake. The AMD system proves to be effective and efficient within a certain range of the ball screw pitch. The reductions of the peak responses can reach as high as 70% if properly designed. Requiring only the velocity measurement of the top floor for on‐line feedback control, the proposed control algorithm is recommended for practical implementation. Copyright © 2004 John Wiley & Sons, Ltd.     

The Shape and Volume of the Skaergaard Intrusion, Greenland: Implications for Mass Balance and Bulk Composition

Re-examination of the Skaergaard intrusion in the context ofits regional setting, combined with new data from explorationdrilling, has resulted in a revised structural model for theintrusion. It is modelled as an irregular box, c. 11 km fromnorth to south, up to 8 km from east to west, and 3·4–4km from the lower to the upper contact. The walls of the intrusionare inferred to follow pre-existing and penecontemporaneoussteep faults, and the floor and roof seem largely controlledby bedding planes in the host sediments and lavas, similar toregional sills. The suggested shape and volume are in agreementwith published gravimetric modelling. Crystallization alongall margins of the intrusion concentrated the evolving meltin the upper, central part of the intrusion, best visualizedas an ‘onion-skin’ structure inside the box. Thetotal volume is estimated to c. 280 ± 23 km³, of which13·7% are referred to the Upper Border Series (UBS),16·4% to the Marginal Border Series (MBS) and 69·9%to the Layered Series (LS). In the LS, the Lower Zone (LZ) isestimated to constitute 66·8%, the Middle Zone (MZ) 13·5%and the Upper Zone (UZ) 19·7%. The new volume relationshipsprovide a mass balance estimate of the major and trace elementbulk composition of the intrusion. The parental magma to theSkaergaard intrusion is similar to high-Ti East Greenland tholeiiticplateau basalts with Mg number c. 0.45. The intrusion representsthe solidification of contemporary plateau basalt magma trappedand crystallized under closed-system conditions in a crustalreservoir at the developing East Greenland continental margin. KEY WORDS: bulk composition; emplacement; mass proportions; Skaergaard intrusion; structure