Analysis of mechanical properties and microscopic mechanism of dredger fill in alkaline environment
LEI Huayang1，2，WANG Lei1，TU Cike1，HAN Jun3，JI Zhiyong3
(1. Department of Civil Engineering，Tianjin University，Tianjin 300072，China；2. Key Laboratory of Coast Civil Structure Safety of Education Ministry，Tianjin University，Tianjin 300072，China；3. China Railway 16th Bureau Group the 5th Engineering Co.，Ltd.，Tangshan，Hebei 064000，China)
Abstract：Chemical environment has a significant effect on the mechanical and microscopic characteristics of the dredger fill. In this paper，a set of laboratory tests were carried out to look into the strength，deformation as well as the microscopic structure of dredger fill with various NaOH content，including direct shear test，triaxial shear test，one-dimensional compression test and microscopic test. The experimental results show that the shear strength and structural yield stress increase by 15.1–79.3 and 5–169 kPa respectively，and the reason is that the intergranular cement strength was greatly enhanced due to the insoluble substances generated in the alkaline environment. Moreover，the stress-strain relationship of dredger fill changes from strain hardening to strain softening in the alkaline environment，meanwhile，the compressibility being greatly reduced with the maximum reduction of the compression index being 60.3%. Finally，the intergranular cement of the dredger fill in the alkaline environment develops well. The particle morphology is transformed from granular structure and flaky structure to agglomerate structure，and the surface-to-surface contact is the main form of the intergranular connection.
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2019, Vol. 38 
