含砂量对水泥土强度影响的试验研究

天然软土尤其三角洲地区的淤泥或淤泥质黏土常含砂，以含细砂或粉细砂为主，系统研究水泥土强度与含砂量的关系，为水泥土性能改良、强度设计及水泥土搅拌法施工提供直接依据。选取珠江三角洲两处典型的淤泥、淤泥质黏土，按天然含水率配制试验用土，掺加不同含量的细砂制成含砂水泥土试件，养护到不同龄期，对其进行无侧限抗压强度试验，得到了水泥土强度与含砂量及其他关联影响因素关系的变化规律。主要结论是：细砂颗粒在水泥土中起到了细骨料的作用，有利于提高水泥土强度；考虑水泥土的含砂量、水土质量比、水泥掺入比和实际水灰比等因素，得到了含砂淤泥水泥土强度估算公式；在不含砂淤泥水泥土中掺入2 %干细砂时其强度约提高25 %，掺入15 %~25 %干细砂则可提高40 %~60 %。

Experimental study on effect of sand content on strength of soil-cement

Sand usually exists in natural soft soil, especially in silt or mucky soil in the delta. The systematic investigation into the effect of sand content on the strength of sandy soil-cement mixed with silt or mucky soil can directly provide useful data for the design and construction of soil-cement mixing piles. The typical silt and mucky soil were drilled from two places in the Delta of the Pearl River. The fine sands with different contents were added to the soil samples with natural water content to make the samples of sandy soil-cement. The samples of sandy soil-cement were then cured for different ages, for the measurement of unconfined compression strength. Therefore, the variation laws of the strength of sandy soil-cement with sand content and other influence factors were obtained, thus coming to the conclusions and the unconfined compression strength of the sandy soil-cement obviously increases because sand exists as a role of fine aggregate, that the unconfined compression strength of the sandy soil-cement with 0.02 to 0.25 in sand content is 0.25 to 0.60 times higher than that of soil-cement without sand; and the formula for estimating the unconfined compression strength of sandy soil-cement was obtained by considering the influence factors including sand content, mass ratio of water to soil particle, mass ratio of cement to soil particle and the practical mass ratio of water to cement.