To achieve the purpose of storing industry solid wastes and enhancing subgrade stability in a seasonally frozen region, Structure III, which utilized modified silty clay (SC) and extruded polystyrene (XPS) board as a novel subgrade thermal insulation layer (NSTIL), was presented.

上段的Structure III, silty clay (SC)，NSTIL我在后面书写过程中多次用到，不知道前面要不要加the，如下段：

In terms of the thermal insulation capability, the numerical simulation of coupling moisture and temperature was applied to analyze that of the Structure I, II and III. The research results show that both of the modified SC and NSTIL have the advantage of good thermal insulation property, but thermal insulation property of the NSTIL is greater than that of the modified SC.

请老师帮忙指出上述的the的使用有问题吗？能提点意见更好了!