Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong水工程施工水工程施工Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong水工程施工水工程施工Shui Gong Cheng Shi GongShui Gong Cheng Shi Gong第一章第一章 土石方工程与地基处理土石方工程与地基处理Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong一、土石方工程重要性：一、土石方工程重要性： 土石方工程是工程施工中的主要项目之一，土方开挖、填筑、运输等工作所需的劳动量和机械动力消耗均很大，往往是影响施工进度、成本及工程质量的因素。Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong二、土石方工程施工特点：二、土石方工程施工特点： （1）影响因素多且施工条件复杂 土壤是天然物质，种类多且成分较为复杂，性质各异又常遭遇地下水的干扰。组织施工直接受到所在地区的地形、地物、水文、地质以及气候诸多条件的影响极大。施工必须具有针对性。 Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong（2）量大面广且劳动繁重 如给排水管道施工属线型工程，长度常达数公里，甚至数十公里，而某些大型污水处理工程，在场地平整和大型基坑开挖中，土石方施工工程量可达数十万到百万立方米。对于量大面广的土石方工程，为了减轻劳动强度，提高劳动生产率，加快工程进度，降低工程成本，应尽可能采用机械化施工来完成。 Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong （3）质量要求高，与相关施工过程紧密配合 土石方施工，不仅要求标高和断面准确，也要土体有足够强度和稳定性。常需与相关的施工排水、沟槽支撑和基坑护壁、坚硬岩土的爆破开挖等施工过程密切配合Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong 施工前要作好调查研究，搜集足够的资料，充分了解施工区域地形地物、水文地质和气象资料；掌握土壤的各类和工程性质；明确土石方施工质量要求、工程性质、施工工期等施工条件，并据此作为拟定施工方案、计算土石方工程量、选择土壁边坡和支撑、进行排水或降水设计、选择土方机械、运输工具及施工方法等的依据。Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong 在给水排水管道和构筑物工程中，常会遇到一此软弱土层，当天然地基的承功力不能满足要求时，就需要针对当地地基条件，采用合理、有效和经济的施工方案，对地基进行加固或处理。 三、本章内容：三、本章内容： 土的工程性质及分类； 施工场地平整； 沟槽与基坑开挖、支撑设置； 土方回填与夯实； 地基加固处理； 土石方爆破施工。Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong第一节第一节 土的工程性质及分类土的工程性质及分类一、土的组成 土是由岩石风化生成的松散沉积物，其组成复杂、作用机理复杂。 是由颗粒（固相）、水（液相）和气（气相）所组成的三相体系。Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong（一）土的固体颗粒（一）土的固体颗粒 1、土的颗粒级配 粒组：通常是把大小相近的土粒合并为一组，称为粒组。 粒组分类：不同的粒组具有不同的性质，工程上以尺度为参照，采用的粒组为六大粒组，即漂石、卵石、圆砾、砂粒、粉粒及粘粒。Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong土粒粒组的划分 表1-1 砂粒和粉粒的界限粒径，规范砂粒和粉粒的界限粒径，规范GBJ7-89采用采用0.075mm。粒 组 名 称粒径范围（mm）一 般 特 征漂石或块石颗粒200透水性大，无粘性，无毛细水卵石或碎石颗粒20020透水性大，无粘性，无毛细水圆砾或角砾颗粒202透水性大，无粘性，毛细水上升高度不超过粒径大小砂 粒20.05易透水，当混入云母等杂物时透水性减小，而压缩性增加；无粘性遇水不膨胀，干燥时松散；毛细水上升高度不大，随粒径变小而增大粉 粒0.050.005透水性小；湿时有粘性，遇水膨胀小，干时稍有收缩；毛细水上升高度较大较快，极易出现冻胀现象粘 粒0.005透水性很小；湿时有粘性，可塑性，遇水膨胀大，干时收缩显著；毛细水上升高度大，且速度较慢Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong颗粒级配： 土中某粒组的土粒含量为该粒组中土粒质量与干土总质量之比，常以百分数表示。而土中各粒组相对含量百分比称为颗粒级配。确定级配方法： 用筛分法和比重计法测定。前者适用于粒径大于0.075mm的土，后者适于粒径小于0.075mm的土。 Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong颗粒级配的表示: 根据土粒分析试验结果，在半对数座标纸上，以纵座标表示小于某粒径的土粒含量百分比，横座标表示粒径（用对数座标），绘出颗粒级配曲线。Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong土粒级配曲线的使用：根据土粒级配曲线陡度可判定土的均匀程度。若颗粒级配曲线陡降，说明该土粒的粒径大小相差不悬殊，土粒较均匀，级配不好；若颗粒级配曲线平缓，说明该土粒的粒径大小相差悬殊，土粒不均匀，级配良好。Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong不均匀系数Ku：评价土的均匀程度的指标用其表达式为： 式中 d10小于某粒径土粒质量累计百分数为 10%时对应的粒径，称为有效粒径； d60小于某粒径土粒质量累计百分数为 60%时对应的粒径，称为限定粒径。 在工程上Ku5时土是不均匀的，但级配良好。Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong2、土粒的矿物成分、土粒的矿物成分 l土的固体颗粒构成土的骨架，是由矿物所组成的。l组成固体颗粒的矿物有原生矿物、次生矿物和有机化合物。Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong碎石土和砂土颗粒组成：碎石土和砂土颗粒组成： l由原生矿物所组成，即由石英、长石和云母等组成，即大颗粒变为小颗粒的简单机械破碎。 Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gongl粉粒的矿物成分:石英和难溶的盐类CaCO3、MgCO3等颗粒。l粘粒的矿物成分:粘土矿物、氧化物、氢氧化物和各种难溶盐类。粘土矿物由于晶片结合情况不同，有蒙脱石、伊里石和高岭石三类。 Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gongl高岭石的晶格结构较为稳定，亲水性小，故其膨胀性和可塑性较小，对于其它物质的吸附能力也不大。l蒙脱石与高岭石比较起来，具有截然不同的性质。蒙脱石的晶格结构不稳定，水容易渗入，亲水性就大，它与水结合的能力远高于高岭石当它与水作用时，具有极大的膨胀性、可塑性。我国湖北、安徽和西南地区有一种膨胀土，它不仅具有浸水后能严重膨胀，而且具有水分蒸发后又会严惩收缩的性质，这是因为这种土含有大量蒙脱石所致。Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gongl伊里石的性质介于高岭石与蒙脱石之间，但比较接近于蒙脱石。l粘粒组除上述矿物外，还有腐殖质等胶态物质它的颗粒很微小，能吸附大量水分子。Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong（二）土中水和气体二）土中水和气体l1、土中水l土中水可以处于液态、固态和气态。l当土中温度在0以下时，土中水冻结成冰，形成冻土，其强度增大。但冻土融化后，强度急剧降低, 土中气态水，对土的性质影响不大.Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gongl土中液态水可分为结合水和自由水：l（1）结合水l 结合水是指受电分子吸引力吸附于土粒表面的土中水。由于粘粒表面一般带有负电荷，使土粒周围形成电场，在电场范围内的水分子和水溶液中的阳离子一起被吸附在土粒表面。Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gongl结合水分为强结合水和弱结合水。l强结合水：紧靠土粒表面的结合水。它没有溶解能力，不能传递静水压力，只有在105温度时才蒸发。这种水性质接近固体,具有极大的粘滞度、弹性和抗剪强度。 Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gongl弱结合水:存在于强结合水外围的一层结合水。它仍不能传递静水压力，但水膜较厚的弱结合水能向邻近较薄水膜缓慢转移。粘性土中含有较多的弱结合水时，土具有一定的可塑性。 Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gongl（2）自由水l自由水是存在于土粒表面电场范围以外的水。它的性质与普通水一样，服从重力定律，能传递静水压力，冰点为0，有溶解能力。l自由水分为:重力水和毛细水。 Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gongl重力水：指受重力作用而移动的自由水。它存在于地下水位以下的透水层中。l毛细水：毛细水受到它与空气交界面处表面张力的作用，它存在于潜水位以上的透水土层中。Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gongl2、土中气体l 土中气体有与大气相连通的和封闭的。在粗粒土中常见到与大气相联通的空气，它对土的力学性质影响不大。在细粒土中则常存在与大气隔绝的封闭气泡，它在外力作用下具有弹性，并使土的透水性减小。Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong二、土的三相比例指标二、土的三相比例指标l 土中的土粒、水和气三部分的质量（或重力）与体积之间的比例关系，随着各种条件的改变而变化，土的疏密、轻重、软硬、干湿等性质，可通过某些表示其三相组成比例关系的指标反映出来。 Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gongl用指标、图表示土的三相组成，见下图。Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong指标含义：ms土粒的质量；mw土中水的质量；ma土中气的质量（ma0）；m土的质量：m= ms+ mwVs土粒的体积；Vw土中水的体积；Va土中气的体积；V土的体积：V= Vs+Vw+Va土粒的重力：Gs=msg土中水的重力：Gw=mwg土的重力：G=mgShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong1、土的密度 通常砂土，=1.62.0t/m3；粘性土和粉土，1.82.0t/m3。Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gongl2、土的重力密度 单位体积土所受的重力称为土的重力密度，简称土的重度，并以表示 砂土=1620KN/m3，粘性土和粉土，=1820KN/m3。Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gongl3、土粒相对密度（比重）ds Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong土粒比重参考值土的类别砂土粉土粘性土粉质粘土粘土土粒比重2.652.692.702.712.722.732.732.74Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gongl4、土的含水量 土中水的质量与土粒质量之比（用百分数表示）称为土的含水量，并以表示： 含水量的数值和土中水的重力与土粒重力之比（用百分数表示）相同，即： Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong5、土的干密度、土的干密度d 单位体积土中土粒的质量称为土的干密度，并以d表示： 土的干密度值一般为1.31.8t/m3。 Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong6、土的干重度、土的干重度d l土的单位体积内土粒所受的重力称为土的干重度，并以d表示： Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong7、土的饱和重度、土的饱和重度sat 土中孔隙完全被水充满时土的重度称为饱和重度，并以sat表示： Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong8、土的有效重度、土的有效重度 地下水位以下的土受到水的浮力作用，扣除水的浮力的单位体积上所受的重力称为土的有效重 度，并以表示： Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong9、土的孔隙比、土的孔隙比 土中孔隙体积与土粒体积之比称为土的孔隙比，并以e表示： e1.0的土是疏松的，压缩性高。Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong10、土的孔隙率、土的孔隙率n 土中孔隙体积与总体积之比（用百分数表示）称为土的孔隙率，并以n表示： Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong11、土的饱和度、土的饱和度Sr 土中水的何种与体积之比（用百分数表示）称为土的饱和度，并以Sr表示： 根据饱和度Sr的数值可把细砂、粉砂等土分为稍湿、很湿和饱和三种湿度状态，见表。Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong三、无粘性土的密实度三、无粘性土的密实度l无粘性土定义：l砂土、碎石土统称为无粘性土，它的密实度对其工程性质有重要的影响。Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong判别砂土的密实度的方法判别砂土的密实度的方法：l1、采用天然孔隙比的大小来判别砂土的密实度，是一种较简捷的方法。但不足之处是不能反映砂土的级配和形状的影响。Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong2、用砂土相对密度Dr作为砂土密实度分类指标。相对密度Dr为： 式中：emax砂土最松散状态时的孔隙比； emin砂土最密实状态时的孔隙比； e砂土的天然孔隙比。 若砂土天然孔隙比接近最小孔隙比emin时相对密度Dr较大，砂土处于较密实状态；若e接近emax，Dr较小，砂土处于疏松状态。Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong3、判定界限：根据Dr值可将砂土密 实度划分为下列几种： 1Dr0.67 密实的 0.67Dr0.33 中密的 0.33Dr0 松散的Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong 用相对密度表示砂土密实度，要在现场采取原状砂样以求得土的天然孔隙比，而取原状砂样常较困难。故规范推荐用现场标标准准贯贯入入试试验验锤锤击击数数N确确定砂土密实度，标准如表定砂土密实度，标准如表。砂土的密实度密实度松散稍密中密密实标准贯入试验锤击数NN1010N1515N3030N碎石土可以根据野外鉴别方法分为密实、中密、稍密三种 Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong四、粘性土的物理特征四、粘性土的物理特征 l（一）界限含水量l粘性土随着含水量的增加而分别处于固态、半固态、可塑及流动状态，如图所示。 Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gongl界限含水量：粘性土由一种状态转到另一种状态的分界含水量，称为界限含水量。l液限：土由可塑状态转到流动状态的界限含水量称为液限，用符号wL表示。l塑限：由半固态转到可塑状态的界限含水量称为塑限，用符号wp表示。l缩限：由固态转到半固态的界限含水量称为缩限，用符号ws 表示。l指标都用百分数表示。Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gongl土的界限含水量和土粒组成、矿物成分、土粒表面吸附阳离子性质等有关，是这些因素的综合反映，对粘性土的分类和工程性质评价有重要意义。土的界限含水量和土粒组成、矿物成分、土粒表面吸附阳离子性质等有关，是这些因素的综合反映，对粘性土的分类和工程性质评价有重要意义。 Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong（二）塑性指数和液性指数（二）塑性指数和液性指数 1、塑性指数：液限和塑限是土处于可塑状态的上限和下限含水量。省去%符号后的液限和塑限的差值称为塑性指数，用符号Ip表示，即： 塑性指数全面反映了影响粘性土特征的各种因素，故规范按塑性指数对粘性土分类。 Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong2、液性指数：是判别粘性土软硬状态的指标，是粘性土的天然含水量和塑限的差值（附去%）与塑性指数之比，用IL表示，即： 根据液性指数值，可将粘性土划分为坚硬、硬塑、可塑、软塑及流塑五种状态，其划分标准见表Shui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi GongShui Gong Cheng Shi Gong粘性土状态的划分 表1-5状态坚硬硬塑可塑软塑流塑液性指数IL00IL0.250.25IL0.750.751.0