适用于超盐渍土的固化剂研究

Study on Stabilizers Suitable for Super Saline Soil

随着西部大开发的推进,越来越多的基础设施不得不建设在超盐渍土上。已有研究表明:用现有固化剂固化超氯盐渍土则抗压强度不能满足工程要求;固化超硫盐渍土则因会生成膨胀性的水化硫铝酸钙(AFt)而破坏固化土结构。本研究针对超氯盐渍土开发了固化剂GM1,利用其固化氯盐渍土可以提供满意的固化土强度;对于超硫盐渍土的固化,采用以下两种技术路线可以获得满意的抗压强度、体积稳定性和耐久性:(1)通过降低水化硅酸钙(CSH)的生成速率使其主要在AFt大体生成后才大量生成,以尽可能减小AFt膨胀对CSH胶结形成的固化土结构的破坏;在AFt生成后采用加压工艺弥合AFt膨胀给固化土带来的裂隙;控制固化剂中Ca的含量,保证固化土中后期无自由Ca2+,以断绝AFt形成的必要条件;(2)使用不含晶态的Ca的化合物的固化剂GM2,断绝AFt形成的必要条件。

As the Grand Western Development Program of China has been further promoted,more and more infrastructures have to be built on super saline soil. According to the existing research: when the super chloride saline soil is stabilized,by existed stabilizer the compressive strength is not enough for foundation treatment,and expansive hydrate of calcium aluminate sulfate( AFt) will be generated,which may destroy the structure of stabilized soil. In this research the compressive strength of the soil stabilized by GM1 developed for stabilizing super chloride saline soil is higher. Higher compressive strength,stability of volume and durability can be achieved,when two kinds of technical routes are used to stabilize the super sulfur saline soil. The first is slowing down the generating rate of hydrated calcium silicates( CSH),until AFt is almost generated,and the destruction of stabilized soil structure( which is cemented by CSH) because of the expansion of AFt can be avoided. The fracture of the stabilized soil coming with generation of AFt was healed by the technology of compression and leaving no free Ca2 +in the stabilized soil to eliminate the necessary condition of generating AFt. The second is using stabilizer GM2 without crystalline chemical compound of Ca to eliminate the necessary condition of generating AFt.