Overview of uncoordinated deformation characteristics and treatment techniques research for widening subgrade

Uncoordinated deformation of widening subgrade is one of important factors leading to faults of subgrade and pavement. Formation mechanism of uncoordinated deformation between existing subgrade and widening subgrade is analyzed. Principles and typical characteristics of uncoordinated deformation and its affecting factors including widening modes, widening values, foundation strengths and construction methods are analyzed by choosing a typical cross-section and simulating it with a numerical approach. Treatment effects of subgrade reinforcement upon uncoordinated deformation are investigated by laboratory testing. In addition, applicable conditions and technical essentials of other treatment techniques are analyzed. The results show that formation mechanism of uncoordinated deformation between existing subgrade and widening subgrade under different engineering conditions is different. Treatment measures based on the specific characteristics of the project should be chosen to reduce the value of uncoordinated deformation.