麦秸秆加筋石灰固化盐渍土的破坏形态分析

土的破坏形态是其受力大小与状态的综合反映,也是其内部结构变化的宏观体现。对比分析了不同养护时间、布筋方式和围压下的盐渍土、麦秸秆加筋盐渍土、石灰固化土、麦秸秆加筋石灰固化土试样的三轴剪切破坏形态。结果显示:①盐渍土和麦秸秆加筋盐渍土均呈塑性破坏。其中,盐渍土呈典型的"鼓胀"破坏;受到加筋的约束,加筋土的横向变形小于盐渍土的。②养护前期,石灰同化土和麦秸秆加筋石灰固化土均呈塑性破坏;养护后期,均呈脆性破坏。麦秸秆加筋石灰同化土的破裂面较石灰固化土的不规则,没有类似石灰同化土的对称性破裂块。③低围压下,加筋土的约束力主要来自筋土间的摩阻力,土的破裂纹形态较高围压下的复杂。高围压下,约束力来自筋土摩阻力和围压的共同作用。④麦秸秆的加筋作用可有效地约束和阻止裂纹的发生和扩展。分区布筋时,土样的破坏主要发生于未加筋部位。麦秸秆和石灰共同加筋固化能有效地提高土的抗变形能力,是改善滨海盐渍土的一种可行的处理方法。

Failure Pattern of Reinforced Saline Soil with Wheat Straw and Lime

Failure pattern of soil is the comprehensive expression for the magnitude and status of stress, and displays the microstructure characteristic from macroseopic view. Analysis on shear failure patterns of soil, that of saline soil, reinforced saline soil with wheat straw, lime-soil, and reinforced lime-soil with wheat straw, are carried out. Results present that： （1） Both saline soil and reinforced saline soil with wheat straw display the failure in plastic manner, which showing a typical swelling shape in saline soil. The lateral deformation of reinforced soil is far less than that of saline soil because of reinforcement function. （2） Lime-soil and reinforced lime-soil with wheat straw are all plastic in early curing-day, and brittle in later curingday, however, the fracture surface of reinforced lime-soil is more irregular than that of lime-soil. （3） Fracture of reinforeed soil in low confining pressure condition is more complex than that of in high confining pressure condition, because constraint force mainly comes from reinforced function in low confining pressure, but comes from reinforced and solidified function in high con- fining pressure condition.（4） Reinforced function can constraint deformation, failure position always locate in the un-reinforced position as reinforcing in different areas. Reinforcement with wheat straw and lime can not only more effectively increase anti- deformation and strength of soil, but also solve the shrinkage crack problem of lime soil. As a result, it is an effective method to improve the saline soil by reinforced with lime and wheat straw.