外文翻译土的性质

1.2.2 Water in a Soil Mass

As regards water in the soil,we differ among gravitational water or ground water,capillary water,bound water and interlayer water of a mineral.

1.Gravitational water

The gravitational water is mainly concentrated at contact point between grains that is in steady motion under the influence of gravitational forces.There is a regular water table for the water. Below the water table there exists a water-saturated zone and hydrostatic water within it,The gravitational water has a negative influence on foundation soil.This form of water exists in both coarse-grained soils and finer soils,following Darcy's law.It will be discussed in details in chapter 4.

2.Capillary water

The capillary water,above the gravitational water table,is held by capillary force (surface tension force) that is governed by the surface tension of grains and the diameter of voids.The height, Hc, to which water will rise in a capillary tube (void space) , is, theoretically,directly proportional to the surface tension force T, divided by the diameter of the tube d:

Hc T

d

So the height of the capillary zone (the occupied area of capillary water) will also be affected by the cleanness of the water; it could be much less for pollutes water. According to Terzaghi and Pech (1967) ,the Hc can be giver as:

Hc c

ed10

Where Hc ——maximum height of capillary size, in mm, relates to minimum pore size; e ——void ratio;

d10 ——effective size, mm;

2 c ——constant,10~20 mm (for clean water) .

Capillary rising depends on grain size distribution. As always, the smaller the grain is, the higher the capillary rises, except for some of clay particles that is filled with bound water surrounding the grains. As a geotechnique engineer, you should be aware of a big difference between the capillary water and the gravitational water: the water-saturated zone filled with the gravitational water has hydrostatic pressure, while pore water pressure produced by the capillary water should be negative.

3.Bound water

In the fine-grained soils,the grain surface has an ionized layer around them, which is defined as bound water. More and more people have known that the cohesion force,which is against shearing stress, is to a large extent, resulted from the bound water. The plastic properties of clay soil such as swelling and shrinkage of clay, is mainly attached to the bound water. It is a very important factor considered in the design of a foundation. See Fig. 1-4.

4.Interlayer water

The interlayer water is hidden in a mineral. For example, the mineral,montmorillonitic has a layer structure, its interlayer space,is typically filled with water,originally filled, or filled later. Depending on the abundance or deficiency of water occupy this space, a montmorillonitic soil may exhibit its marked properties of swelling and shrinkage.The montmorillonitic soil, as a loaded

foundation, is very unstable when water is present.

1.2.3 Gas in a Soil Mass

As always, gas basically exists in a soil mass. We differ between opened gas and closed gas. The opened gas is interconnected, and directly flows to atmosphere, while the closed gas retains.The former always takes place in the coarse-grained soil,which has little influence on the engineering properties of the soil. But the latter is so difficult to escape that there is a high compressibility and a low permeability for the soils.Geotechnical engineers should know that the presence of gas in the soil void is of great importance in the design of a foundation.

1.2.4 The Structural Features of a Soil Mass

1.Different Layers of Soil

For the sedimentary formations, no matter whether they are wind-deposited,water-deposited or glacial-deposited, it is natural that there are different layers of soil,fine-grained soil or coarse-grained soil.Fine-grained layers are often embedded in coarse-grained layers and vice versa. We can also say,from the soil mechanics point of view, high bearing capacity (or Low compressive) layers are often embedding in low bearing capacity and vice versa. These different layers of soil will cause the problems as follows:

（1）Long-term settlement if there are weak layers (existed).

（2）Differential settlement of buildings (superstructure) due to the layers' thickness change in horizontal direction.

（3）Landslide along a thin and weak layer (such as clay or silt) when deep excavating for foundation.

It is emphasized that the weak layers of soil will be carefully studied in the building site for a successful foundation design.

2.Non-homogeneities (Homogeneousness)

Absolutely, soils are non-homogeneities materials that are different in deformation and strength in all directions. The non-homogeneities characteristics of soil are caused by not only the variation of deposit conditions, but also the effect of stress history. With a very large variations in size and shape, most of which are sharp-edged belonging to the former, while deep-going fissures and cracks are the latter. In engineering investigation of a soil mass, we should pay attention to the local non-homogeneities such as lenses of highly compressible soils embedded in the formations that are of particular danger and often cause detrimental and big differential settlement of buildings.

1.3 Soil Configuration

1.3.1 Single-grained Structure

The primary structure for a coarse-grained soil is typically single-grained one. The loose configuration shown in Fig. 1-5 (a) typically takes place in an active water environment such as beach sand or river gravel. But the dense soils as shown in Fig. 1-5 (b) are typically originated in a quiet water environment. The soil with single-grained structure may serve as a natural foundation soil.

1.3.2 Honeycomb Structure

For the very fine sand or silt soil, the grain arrangement looks like the honeycombs of a bee, in term of honeycomb configuration similar to that shown in Fig. 1-6. The soil with the honeycomb configuration has the properties of loose, low strength and high compressibility.

1.3.3 Fabric Structure

Clay soil has its special structure, fabric configuration shown in Fig. 1-7. This concept of soil structure is arrived at through the current microscopy technique. Some clay grains may exists in randomly arranged picket or pads, which individually are made up of highly oriented particles. For this configuration, you should be aware of high compressibility due to high voids in the design of a foundation.

Macro structure of a soil mass, such as beds,disappeared layers, lenses and deep-going fissures, are very dangerous because they are the cause of high compressibility, low strength and differential settlement.

1.4 The Important Parameters for Two-phase and Three-phase Soils

From the construction point of view,soils are also divided into in situ soils that are in place and undisturbed, and artificial soil by human beings such as embankment.Both in situ and disturbed soil usually have solid, water, and air, known as three-phase soils, which can be expressed in a schematic as shown in Fig. 1-8. All parameters are expressed in terms for a soil mass (three-phase soil).

1.4.1 Measurement of Voids

Voids in soil are either expressed in terms of porosity or in terms of void ratio. Porosity n is defined as the ratio of volume of voids,Vv, to total volume of soil V and expressed as a percentage, while void ratio e is defined as the ratio of volume of voids to volume of particle Vs, expressed as a decimal. They are differently expressed without any reason other than custom .

1.2.2 土中的水

关于土中的水，我们可分为重力水或地下水，毛细水，结合水和矿物隔层水。

1. 重力水

重力水主要集中在介于颗粒间的接触点，在地心引力的影响下固定移动。这有一个规律的地下水位。在地下水位的下面存在一个水饱和层和静力水在里面，重力水对地基土有消极影响。水的形态存在粗粒土和优质土中都符合达西定律。这将是在第四章中详细讨论。

2. 毛细水

毛细水，在重力水位上面，是由颗粒的表面张力和孔隙率的直径管理毛细管力(表面张力力)。高度

Hc Hc，在毛细管（孔隙空间）中水将会上升，从理论上来讲，与表面张力力T成正比，除以管的直径d： T

d

所以毛细管水层的高度（毛细水的占地面积）也将受到洁净水的影响；这更不用说是污水了。根据太沙基和Pech（1967），Hc由

给出。

HcHc ced10——毛细管径的最大高度，单位mm，与最小孔径有关；

e ——空隙比；

d10——实际直径；

2c ——常数，10~20mm（对于洁净水）。

毛细上升取决于粒度分布特征。像往常一样，越小的颗粒，毛细上升得越高，除了一些周围充满了结合水的粘土颗粒。作为一名土力学工程师，你应该知道介于毛细水和重力水的一个很大的区别：充满重力水的饱和水区有静水压力，而由毛细水产生的孔隙水压力应该是消极的。

3. 结合水

在细粒土中，颗粒表面有一个电离层围绕着它们，这被定义为结合水。越来越多的人们知道了内聚力，这反对抗剪应力，在很大程度上，是由结合水造成的。粘土塑性如粘土的膨胀和收缩，是主要系于结合水。这在地基的设计中是作为一个重要因素来考虑的。见图1-4。

4. 层间水

层间水隐藏在矿物中。例如，矿石富含有一层结构，其夹层空间是典型的装满水，原来满,或填充之后。依靠水的丰富或缺乏占领这个空间，富含土壤彰显其明显肿胀和收缩性能。作为装载基础，当水存在时，肥沃土是非常不稳定的。

1.2.3 土中的气

像往常一样，气体主要存在在土体中。我们可分为非闭合气体和闭合气体。非闭合气体是连通的，直接流向大气的，而闭合气体保留了下来。前者通常发生在粗粒土中，这在土的工程性质中几乎没有影响。但后者是如此难以逃脱，因为土壤有高压缩性和低渗透性。岩土工程师应该知道在土壤空间中存在气体对基础的设计有着重要意义。

1.2.4 土体的结构特点

1. 土的不同层

对于沉积地层，无论是否风积，水积或冰积，这有不同层的土，粗粒土和细粒土，是自然的。细粒土经常嵌入在粗粒层，反之亦然。我们也可以说，从地质力学的观点，高承载力（或低抗压）层经常嵌入在地承载力，反之亦然。这些土的不同层将导致以下这些问题：

（1）如果有软弱夹层（存在）长期的沉降。

（2）由于地层的厚度在水平方向发生改变，导致上层建筑的不均匀沉降。

（3）当为了基础而深度挖掘时，会沿着一个薄弱的底层（如黏土或淤泥）山崩。 这就强调了在一个建筑工地的成功的基础设计中要认真研究土的软弱夹层。

2. 不均匀性（均质性）

绝对的，土是不均匀物质，它在不同方向的变形和强度都是不相同的。土的不均匀性特征不仅由沉淀物情况的变化引起，而且由应力史作用引起的。随着尺寸和形状非常大的变化，其中属于前者的大部分是边缘清晰的，而深刻的裂缝是后者。在土壤质量的工程勘察中，我们应该注意局部的不均匀性，如埋在地层的镜片高压缩性土具有特定的危险和常常会对建筑

物造成很大的不均匀沉降。

1.3 土的结构

1.3.1 单粒结构

粗粒土的主要结构式典型的单粒结构。如图1-5（a）所示，疏松结构典型地发生在活性水环境中，如沙滩沙或河沙石。但如图1-5（b）所示，典型地发生在静水环境中。单粒结构的土可以起一个自然基础土的作用。

1.3.2 蜂窝状结构

对于细沙或粉砂粘土，颗粒排列好像蜜蜂的蜂窝，在蜂窝外形方面与图1-6所示的相似。蜂窝状的土有疏松性，低强度和高压缩性。

1.3.3 絮状结构

粘土有其特殊结构，絮状结构如图1-7所示。土结构的这个概念是通过电流显微镜技术得出的。一些粘土颗粒可能存在随机安排在桩或垫，这单独地由高导向粒子组成。对于这个结构，由于在基础设计中的高孔隙率，你应该注意高压缩性。

土体的宏观结构，如地层，消失层，镜头和深刻的裂缝，是非常危险的，因为它们造成了高压缩性，低强度和不均匀沉降。

1.4 二相土和三相土的重要参数

从建筑的角度来看，土壤也分为原位土即在原地和无扰动的，和人工土如堤岸。原位土和扰动土通常都有固体，水和空气，成为三相土，可以用图1-8中所示的示意图表示。所有的参数表现为一种土体(三相土)。

1.4.1 孔隙率的测量

土中孔隙含量既表达为孔隙度，也表达为孔隙率。孔隙度n解释为孔隙体积总体积V之比，用百分比表示；而孔隙率e解释为孔隙体积

表示。他们是不同的表示没有任何理由以外的习俗。 VVVV与土的与固体颗粒体积VS，用小数

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