关键词: 黄土, 木质素磺酸盐, 单轴抗压强度, 加卸载试验, 应力松弛, X射线衍射

Abstract: As an important mean for soil reinforcement, chemical solidification can consolidate soil particles with the reaction of chemical materials. Lignosulfonates are used to consolidate loess. Based on the limit moisture content test, thermal conductivity test, uniaxial compressive strength test, loading-unloading test, stress relaxation test and x-ray diffraction, the physical property and mechanical properties of lignosulfonate solidified loess are studied; and then the reinforcement mechanism of lignosulfonate is analyzed from the angle of energy dissipation and mineral phase. The reaearch results show that under air-dry conditions sodium lignosulfonate aggravated salinization of loess, and show unsatisfactory effect on improving the strength of loess. But with the increase of calcium lignosulfonate’s dosage, the plasticity index and thermal conductivity of solidified loess reduced; and the strength of samples improved significantly. For instance, the uniaxial compressive strength of loess even reached 11.81 MPa with 5% addition amount of calcium lignosulfonate and the curing age of seven days. The stiffness of the solidified loess is significantly increased under the action of calcium lignosulfonate, under the same strain level the energy consumption is greatly increased and the rate of stress relaxation is improved. Results of X-ray diffraction tests assisted that calcium lignosulfonate can react with the clay minerals in the loess to produce quartz and carbonate minerals, so as to strengthen the siliceous and calcareous cementation between the soil particles; finally, make the soil structure more compact. It is a new type of curing material worthy of further study.

Key words: loess, lignosulfonate, uniaxial compressive strength, loading-unloading test, stress relaxation, X-ray diffraction