MODEL EXPERIMENTAL RESEARCH ON WETTING DAMAGE MECHANISM OF WIDENING LOESS ROADBED
WENG Xiaolin1，2，LI Lintao3，ZHANG Liujun2
(1. Key Laboratory for Special Area Highway Engineering of Ministry of Education，Chang¢an University，Xi¢an，Shaanxi 710064，China；2. CCCC First Highway Consultants Co.，Ltd.，Xi¢an，Shaanxi 710068，China；3. Henan Zhongyuan Expressway Co.，Ltd.，Zhengzhou，Henan 450052，China)
Abstract：To study the wetting mechanism of widening loess roadbed and its failure modes，the deformation measurement system is installed on geotechnical centrifuge. To achieve the actual stress with the loess embankment broadening，the Xi¢an—Tongguan Expressway is adopted. The results show that the widening embankment slope toe with high water content will influence loess roadbed stability in the zone with shallow water level. During the heavy rainfall or the sudden jump of the water level under the embankment load，the local loess soil instability will greatly threaten the safety of the widened embankment，and the flooding-damaged formation of slip surface is a progressive failure process. Due to local swampy ground and low shear strength，initial shear failure of foundation will occur on the old road slope once the foot of the wetting slope causes excessive distortion generated by the global body from top to bottom of the slip slope. The sliding surface of loess roadbed is approximately circular shape，and the method for stability evaluation of the foundation under widening load is proposed using fissures arching. The results also show that the new and old roadbeds with reinforced materials in soils attached to the role can form an effective soil arching effect，they can make the best of embankment rigidity to adjust deformation of the foundation settlement.
