三,一般墙下条形基础的类型及要求墙体基础最常采用的是刚性条形基础,通常用砖或毛石砌筑,为了保证基础的耐久性,砖的标号不宜低于75号,毛石需用未风化的坚硬岩石。砌筑时,在地下水位以上可用混合砂浆,地下水位以下则要用水泥砂浆,砂浆标号一般不低于50号。亦有采用混凝土条形基础的,混凝土标号可用100号或75号。在我国华北和西北地区还广泛采用灰土条形基础,灰土是用石灰和土配制成的(体积比3∶7或2∶8)。石灰以块状生石灰为宜,经消化1—2天后立即使用,土料为塑性指数较低的粘性土,灰土基础宜在比较干燥的地区使用。在我国南方,则常用三合土(1∶2∶4或1∶3∶6石灰、砂和骨料)做基础。灰土和三合土基础都是在基槽内分层夯打而成的,见图4。 III. Types and requirements of general strip foundations under the wall The most commonly used wall foundations are rigid strip foundations, usually made of bricks or rubble. In order to ensure the durability of the foundation, the number of bricks should not be lower than 75. Rubble requires unweathered hard rock. When masonry, mixed mortar can be used above groundwater level, cement mortar should be used below groundwater level, and mortar number is generally not less than No. 50. There are also concrete strip foundations, with 100 or 75 concrete markings. In China’s north and northwest regions, a grey soil strip foundation is also widely used. Ash soil is made of lime and soil (volume ratio 3:7 or 2:8). Lime is a blocky quicklime, which is suitable for use after digestion for 1-2 days. The soil material is a clay with a lower plasticity index. The lime soil foundation should be used in relatively dry areas. In southern China, triads (1:2:4 or 1:3:6 lime, sand, and aggregate) are commonly used as the basis. The foundations of lime soil and triaxial soil are all stratified and struck in the base trough, as shown in Figure 4.