Study On The Soft Soil Treatment Of Western Sea Embankment Of Shenzhen City

The western sea embankment of Shenzhen City was constructed under the condition of lack of geological data. After the construction, the sea embankment subsided, the surface is out-of-flatness, the wave wall cracked, and the sluice is lean. The main reasons for these phenomena are the uneven settlement of the embankment caused by the softness of geology. The original embankment only resists the high tide which emerges once in 20 years and the wind-wave scale of ten-grade. However, with the rapid economic development of Shenzhen City, the western sea embankment should resist the high tide which emerges once in 100 years and the wind-wave scale of twelve-grade. On the other hand, the airfield's embankment section need be constructed, which fall across the soft silt foundation. The thesis brings forward two methods for the foundation treatment of the constructed embankment and constructing embankment, which are cement deep mixing and plastic drain board, respectively. The two foundation treatments are validated effective. The main work of the thesis follows:(1) the work of ground improvement for the constructed embankment. The strength of original cement deep mixing piles is very low at the range of 0.2-0.5MPa, and the content of cement is not uniform at the altitude of pile. So the thesis has made the indoor experiments of mixture ratio, and the improved construction workmanship. On the basis of the achievement of the tests and the cross-section change of the embankment, the design has been optimized and the engineering capital invest has been saved.(2) the optimization work of fill-up schemes for the building embankment. The thesis has studied the scheme feasibility of plastic drain board. The two-stepped embankment scheme has higher safe stability than the one-stepped embankment scheme. On the other hand, the FEM model also validates the two-stepped scheme safe.