Frost-heave properties of saturated compacted silty clay under one-side freezing condition

In seasonally frozen regions, the frost-heave properties of soil play a significant role in its upper-structure performance and durability. To investigate the frost-heave behaviors of saturated, compacted silty clay soil widely used as subgrade material, a series of one-side freezing tests was carried out; and the freezing depth and frozen front effected by the compactness, temperature, overburden pressure, and water-supply condition were analyzed and discussed. The results show that the moving speed of the frozen front and growth rate of the frozen depth are positively correlated. The frost heave is maximum in the frost-heave stability condition. The frost ratio of saturated soil is proportional to the water supply and cooling temperature under a one-side freezing condition. The frost ratio of saturated soil is inversely proportional to the initial compactness of the soil specimen and the overburden pressure.     

祁连山地震带两次中强地震前的加卸载响应比异常

研究了祁连山地震带两次中强地震前的加卸载响应比异常特征，讨论了基于天然地震序列的样本条件对加卸载响应比计算结果的影响，提出处理序列中4．0级以上地震的新方法。     

Seismic Response of Base-Isolated Structures underMulti-component Ground Motion Excitation

INTRODUCTIONConcept of base isolation has attracted considerable attention in recent years (Sun et al., 1994). The basic isolationsystem consists of an array of bearings between the base of thebuilding and its foundation. It shifts the fundamental frequencyof the structure away from the energetic region of the earthquake spectrum and limits the earthquake energy transmitted tothe superstructure (Tang and Liu, 1993 ). Base isolation isused widely to protect structures from the destructive…     

An Improved Method for Calculating Paleoheat Flow from Vitrinite Reflectance Profiles

lNTRODUCTIONIt is wel1 established that the vitrinite reflectance (R<, ) de-pends on the temperature history that a basin has undergone.In general, Ro is a function of maximum paleotemperature andeffective heating time. Thus, the paleotemperature of sedi-ments and the value of vitrinite ref1ectance are controlled by theflow of heat Q(t) into the basin and by the thermal parametersof the sediments. Therefore, in principle, it is possible to cal-culate the thermal vitrinite reflectance of …     

南极15ka以来海洋沉积物的环境磁学研究

通过对东南极普里兹湾陆坡区ＮＰ９５－１及西南极长城湾ＮＧ９３－１两柱样系统的环境磁学研究，获得了南极地区１５．０～５．５ｋａＢ．Ｐ．以来的古气候变化序列。结果表明，磁学参数较好地记录了古气候变化及沉积环境变化的信息。ＮＰ９５－１柱样较好地记录了Ｈｅｉｎｒｉｃｈ１事件、新仙女木事件以及波令－阿罗德暖期，其中Ｈｅｉｎｒｉｃｈ１事件发生于１４．３ｋａＢ．Ｐ．，新仙女木冷期为１１．７～１０．３ｋａＢ．Ｐ．，１０．３ｋａＢ．Ｐ．以后，南极地区进入全新世。在全新世，两柱样记录了在１０．０ｋａＢ．Ｐ．及６．０ｋａＢ．Ｐ．前后两个暖期，其间夹有小幅气温下调的时段；６．０ｋａＢ．Ｐ．后，两柱样均有气候颤动变冷的记录。     

面部和颅底骨折的CT分析

为了提高对面部和颅底骨折的认为。本组７４例，男性６３例，女性１１例，年龄２－７１岁，车祸外伤６４例，拳击伤５例，铁棍击伤２例，从高处跌下３例，全部病例均采用轴位ＣＴ平扫。眶内壁骨折２０例，其中爆裂骨的１１例，直接骨折８例，１列同时受直接和间接外力作用；眶下壁骨折１例，为爆裂骨折；眶外后壁骨折１例，眶顶壁骨折９例，均为直接骨折；其他骨折３３例；蝶窦内液平为颅底骨折的重要间接征象。ＣＴ检查可确定骨折类     

县级泥石流信息系统的建立及其应用──以四川省丹巴县为例

本文根据软件工程的原理和方法阐述了县级泥石流信息系统的建立过程，并讨论了其应用，主要包括数据库管理系统的应用，用图形库的应用，系统支持下的泥石流危险度分区，泥石流两类分别判别模式的建立。     

河东煤田地史—热史模拟与煤变质演化

河东煤田是华北石炭二叠纪重要煤田之一．本文采用盆地数值模拟方法,建立了煤田地史一热史模型,恢复了煤变质演化历程,总结出煤级分布规律。     

地震通信电台架设最佳方法的初探

本文着重讨论了地震通信电台的合理布网,电台天线和电台架设中的问题。并提出了电台架设中应该注意解决的一些共性问题,其目的是为了对地震通信用电台架设的最佳方法进行一次试验性的初探。