Effect of asymmetry and irregularity of seismic waves on earthquake-induced differential settlement of buildings on natural subsoil

The effect of asymmetry and irregularity of the inputted seismic waves on the earthquake-induced differential settlement of the buildings on natural subsoil is investigated in terms of the earthquake damage phenomena, theoretical analyses, dynamic triaxial tests and shaking table tests. A conclusion can be drawn from the investigation results that, the asymmetrical and irregular character of the inputted seismic waves themselves may have a significant contribution to the differential settlement of subsoil and buildings in some cases, and this is a necessary factor to be considered in reasonable evaluation for the differential settlement and other problems relating to the soil deformation due to earthquakes.     

西藏南部郎杰学群碎屑物质来源的古水流证据

新近对西藏山南琼果和贡嘎地区(特提斯喜马拉雅北亚带)弱变质的上三叠统深海—半深海沉积地层——郎杰学群地质填图调查,在出露槽模沉积构造的37个古水流点获得了43组数据。赤平投影数据恢复后发现,这一地区主力古水流有南东140°～160°和南西190°～210°两个方向。这一分析结果为郎杰学群沉积物来自北边(未知块体)而非印度次大陆的观点提供了有力证据。     

On Rhythmical Layering of Rocks Formed from Basaltic Magma

Formation of rhythmical layering in intrusive basic and ultrabasic rock bodies is explained in different ways, in particular, by the movement of microparticles (mineral clusters) of plagioclase and pyroxene within the basalt melt under the influence of thermal and gravitational forces. A model of cluster movement is proposed as a consequence of the forces appearing when ultrasonic elastic fluctuations pass through the melt. The model is based on fundamental dynamic equations. Depending on cluster density, wave parameters, and magmatic chamber size, in the melt there can form different combinations of rhythmically alternating layers of different composition.     

瑞雷面波在防渗墙无损检测中的应用

瑞雷面波均匀介质理论和弹性层状介质中的频散理论都是在半无限弹性空间基础上进行的，本文通过理论分析将瑞雷面波引申在水平方向宽度有限的墙状介质中应用，结合室内实验和防渗墙施工问题，得出一套完整的无损检测技术，用以控制防渗墙施工质量。     

Helmholtz算子逆的多方向分裂

Fourier有限差分(FFD)方法是一个重要的波场深度延拓方法，它需要用到包括Taylor展开、连分式晨开、迭代展开等一系列数学展开，将FFD方法从二维推广到三维时，需要解决二维Helmholtz算子的求逆问题。本文利用多方向分裂方法导出了二维Helmholtz算子逆的近似公式，可以应用于三维波场深度延拓问题的研究。     

检层法钻孔S波速测量中的震相问题

在岩土工程测量中，Ｓ波速度是一个重要参数，正确地识别其震相，对提高Ｓ波速度的测试精度非常重要。郭铁拴先生等发表关于“检层法鲇孔波速测量中的震相分析”一文中提出在有套管的检层Ｓ波测量中，深度大于４０ｍ时，Ｓ波震相淹没在折射波中。     

对称不稳定大气中的孤立行波精确解

通过对二维准动量无辐散、无摩擦、密度非均匀分布的层结大气中基本气流切变对非线性方程组行波解的影响问题的研究，证明：（ａ）在对称稳定（ｑ＝Ｎ２Ｆ２－Ｓ４＞０）的大气中：非线性行波解为周期解，且其周期与相应的线性周期解的周期相等；（ｂ）在对称非稳定（ｑ＝Ｎ２Ｆ２－Ｓ４≤０）的大气中：存在两类非线性行波解，其性质是由参数Ｂ决定的。Ｂ＝（Ｎ２ｓｉｎ２φ－２Ｓ２ｓｉｎφｃｏｓφ＋Ｆ２ｃｏｓ２φ）／σ２。（１）当Ｂ＞０时为周期解，且其周期与相应的线性周期解的周期相等；（２）当Ｂ≤０时为孤立波解。