A cids as chemical stabilizers of clay soils

Summary 1. In the acid stabilization of clay soils the aluminosilicate nucleus of the clay minerals is attacked. This process is accompanied by the escape of primarily the aluminum ion from the crystal lattice and the formation of depolymerized silicic acid. As the acid medium is neutralized to pH>3, the latter is condensed into an acid, highly hydrated silica gel, which cements the soil.2. The aluminum and, to a lesser extent, iron, calcium, and magnesium salts formed as a result of exchange reactions play a secondary role in the chemical stabilization process.3. Fluosilicic and phosphoric acids are most effective for treating clay soils. However, treatment with acids does not achieve the long-term stabilization of the surface horizons of soils subject to periodic freezing and thawing or wetting and drying out. Soils stabilized with phosphoric acid are biologically unstable.4. A serious disadvantage of the acid stabilization of clay soils is the technical difficulties associated with the need to mix acid with the soil and the impossibility of its injection into practically impermeable soils. This is an obstacle to the use of acid stabilization in foundation building.Scientific-Research Institute of Foundations. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 4, pp. 22–23, July–August, 1973.     

粘性土层井孔抽水试验的参数识别

粘性土层属于弱透水层,其水流、溶质运移和地球化学过程对于水文地质条件和环境变化具有重要意义.通过抽水试验来获取粘性土原位水力学参数是对粘性土水文地质问题进行研究的必要手段,但由于其渗透性很小,不能采用和常规含水层一样的方法求参.粘性土中的单孔抽水试验与一般含水层中的微水试验具有较大的相似性,因此可以借用微水试验的计算公...     

Geotechnical analysis of two Nigerian soils for use as clay liners

The cretaceous Auchi shale and the Tertiary Imo shale in SW Nigeria were investigated for their suitability for use as a clay seal in waste disposal landfills. Geotechnical analyses indicated they are highly plastic inorganic clays. Although their geotechnical and chemical properties were within the range suggested by various authors for use as mineral seals, care would need to be taken with the Okada shales as they contain smectite and would be difficult to work and liable to cracking.