NaCl与Na_(2)SO_(4)风沙土盐结皮力学特性比较分析

Mechanics Characteristics of Soil Salt Crust Formed by NaCl and Na_(2)SO_(4)

可溶性盐与风沙土胶结形成的盐结皮能提高风沙土抗风蚀能力,减弱沙尘灾害.风沙土中Na^(+)、Cl^(-)、SO_(4)^(2-)三种离子含量较大,因此本文选用NaCl、Na_(2)SO_(4)两种盐与风沙土进行结皮实验.各设置6个盐浓度梯度与风沙土胶结形成结皮,观测盐结皮的表观形态、晶体覆盖度、结皮强度、盐-土胶结颗粒质量、结皮层厚度、结皮应力-进深曲线,探讨两种盐结皮的力学特性.结果表明:含盐量较低时,盐结皮抗压强度和抗风蚀能力受含盐量影响较大;含盐量较高时,盐晶体性质对结皮抗压强度和抗风蚀能力影响较大.Na_(2)SO_(4)的结晶体相变会对结皮结构产生破坏,盐结皮的抗压强度和抗风蚀能力减小.通过对两种盐结皮力学特性的对比分析发现:盐浓度为1.5 mol/L的Na_(2)SO_(4)溶液形成的结皮的抗风蚀性能最强.

Soil salt crust can change the loose structure of aeolian soil,improving the resistance of aeolian soil to wind erosion.Three kinds of ions(Na^(+),Cl^(-),SO_(4)^(2-)) with higher content in aeolian soil have been selected for the salt-crust experiment.The experiment had set six gradients of the content of salt.The apparent morphology,crystal coverage,crust strength,thickness of crust,mass of cemented particles in the soil,crust stress-depth curves were observed to study on the mechanics characteristics of two kinds of salt crust.The results showed that when salt content was low,the crust compressive strength and the resistance of aeolian soil to wind erosion were greatly affected by salt content;when salt content was high,crystal shape was an important factor affecting the crust compressive strength and the resistance of aeolian soil.The phase transition of Na_(2)SO_(4)crystallization would destroy crust structure of salt crust,and the compressive strength and wind erosion resistance of salt crust would be decreased.The wind erosion resistance of crust formed by Na_(2)SO_(4)solution with 1.5 mol/L was the best choice by comparing the machanics characteristics of salt crust.