深层搅拌法加固软弱土层的室内实验研究

Laboratory test for treatment of the poor soil using deep mixing method

通过配比实验,用搅拌法对3种软弱土层加固,研究了土质类型、水泥掺入比、龄期、水泥牌号和含水量等因素对水泥土强度的影响。研究结果表明:粘土、亚粘土和粉土加固后的强度依次增大;亚粘土和粉土的水泥土强度分别为粘土水泥土的1.45～4.50倍;水泥掺入比越高,强度越大;水泥掺入比为14%和20%时水泥土强度是水泥掺入比为10%时的1.43～2.48倍;龄期与强度增长成正比,龄期为28d和90d的水泥土强度是7d时的2.2～3.2倍,但水泥土强度的增长速度随龄期的增加而变小;用高标号水泥加固的水泥土强度相对较高,含水量高的土加固后强度要低于含水量较低的土强度;加入粉煤灰和外掺剂能增强水泥土的强度或改善其性能;可根据对加固土的强度与龄期等要求,合理地选择加固参数,以满足实际工程的需要。

The prescription test is made for three different cement-stabilized soils. It is shown that their unconfined compression strength is influenced by the soil types, the cement proportion, the conservation age, cement grade, moisture content and so on. The strength of the cement soils from clay, loam and silt increase successively. For example, the strength of the cement soils from loam and silt are 1.45～4.5 times as large as the soil from clay. The higher the cement proportion, the larger the strength of the cement soil. The strength of the cement soils with 14% and 20% cement are 1.40～2.45 times as large as that with 10% cement. The strength of the cement soils with the 28 and 90 day conservation age is 1.3～2.1 times as large as that with 7 day conservation age. The longer the age of the cement soil, the lower the increase in strength of the cement soil. Moreover, the higher the grade of cement, the larger the strength of the cement soil. The cement soil of the higher moisture content has lower strength. The addition of flyash or other additive to the soil can also increase its strength or improve its properties. According to the requirement of the strength and the age of conservation, the treatment parameters can be selected to satisfy the requirement of practical engineering.