Abstract

Info

Title:: Application Study of Impact Roller Compaction Method to Strengthen Silt Subgrade

Author(s):: SONG Xiu-guang; LI Jin; YU Yi-fan; LI Xin-wei; ZHANG Hong-bo; School of Civil Engineering, Shandong University

Keywords:: impact roller compaction; silt subgrade; virtual paving thickness; water content; compaction degree

Abstract:: According to the characteristics of the Yellow River alluvial plain silt subgrade filling including influence by moisture content, difficult to dry, difficult to compact with ordinary rolling technology, and low production efficiency, the impact roller compaction method was chosen in construction. Through adjusting the subgrade layer thickness and compaction pass number, the impact roller compaction test was conducted to detect the surface settlement, peak valley depth, compaction degree and bearing capacity of subgrade. The impact compression effects of three virtual thickness silt subgrades were compared and analyzed. The results show that compaction degree curve appears inflection point when compaction degree of surface soil reaches or exceeds 93%, and the effect of continue rolling on improving compression degree of soil is getting smaller, then its difficult to improve compaction degree of bottom soil up to 96%. The allowed moisture content ?ω of subgrade filling can be controlled within ?ω^opt-4%≤ω≤ω^opt+4% (ω^opt is optimum moisture content) .The recommend silt virtual paving thickness is 0.8 m, the optimal rolling pass number is 20, the optimal rolling speeds are 10-12 km·h^-1. The surface settlement and peak valley depth should be taking as auxiliary indexes to evaluate the compaction effect..