地基分析与设计------外文翻译.doc

We are concerned with placing the foundation on either soil or rock. This material may be under water as for certain bridge and marine structures, but more commonly we will place the foundation on soil or rock near the ground surface. Soil, being a mass of irregular-shaped particles of varying sizes, will consist of the particles (or solids), voids (pores or spaces) between particles, water in some of the voids, and air taking up the remaining void space. At temperatures below freezing the pore water may freeze, with resulting particle separation (volume increase).When the ice melts particles close up (volume decrease). If the ice is permanent, the ice-soil mixture is termed permafrost It is evident that the pore water is a variable state quantity that may be in the form of water vapor, water, or ice; the amount depends on climatic conditions, recency of rainfall, or soil location with respect to the GWT of Fig. 1-1. Soil is an aggregation of particles that may range very widely in size. It is the by-product of mechanical and chemical weathering of rock. Some of these particles are given specific names according to their sizes, such as gravel, sand, silt, clay, etc., and are more completely described in Sec. 2-7.

人们一般关心基础是坐落在“土体”或是“岩体”之上。对于某些桥梁或海上的结构，其基础可能在水面之下，但更为常见的还是将基础放在地表以下较浅的土体或岩石之上。
土体作为形状不规则、颗粒大小不等的土颗粒的集合，包括土颗粒（或固体）和土颗粒之间的空隙（部分空隙体积被水填充，其余孔隙体积被气体占据）。当温度低于冰点时，空隙中的水将凝结为冰，致使土颗粒分离（也就是体积膨胀），反之，当冰融化为水时，土颗粒又相互靠紧（也就是体积缩小）。如果冰常年不融化，这种冰-土混合物就被称为“多年冻土”。显而易见，孔隙水是一个随机变化的东西，其状态可以为水蒸气、液态水或固态冰。孔隙水量的多少往往会取决于气候条件、近期的降水量或土体的位置（在地下水位之上还是以下），如图1-1所示。