Vertical compression of soft clay within PVD-improved zone under vacuum loading: Theoretical and practical study. Issue 3 (June 2020)

• Record Type: Journal Article
• Authors: Gao, Yan-Bin; Zhang, Zhen
• Is Part Of: Geotextiles and geomembranes. Volume 48:Issue 3(2020:Jun.)
• Page Start: 306
• Page End: 314
• Publication Date: 2020-06
• Subjects: Geosynthetics -- Vacuum preloading -- Soil compression -- Prefabricated vertical drain -- Soil disturbance -- Soft clay; Membranes (Technology) -- Periodicals; Membranes (Technology); Periodicals; Electronic journals; 624.189
• DOI: 10.1016/j.geotexmem.2019.12.003
• Languages: English
• ISSNs: 0266-1144

Abstract

Abstract: Reliably estimating soil vertical compression under vacuum loading is still challenging for geotechnical engineers. In this paper, the soil vertical compression within the prefabricated vertical drain (PVD)-improved zone under vacuum pressure was investigated based on the theoretical analysis, reported laboratory tests and the case histories. A theoretical equation was developed to evaluate the effect of lateral displacement on the soil vertical compression. The observed small overall lateral-to-vertical strain ratio at the perimeter of the PVD-improved zone soil showed that the vertical compression of PVD-improved zone was close to one-dimensional (1-D) state, but 1-D compression method yielded smaller predictions than the measurements from the case histories. The back-analyzed soil modulus of the natural soft clay in Shanghai Disneyland Resort project showed considerable degradation as compared to the corresponding constrained modulus from the laboratory test. Such degradation could be due to the soil disturbance caused by PVD installation. The 1-D compression method was modified by introducing two factors to consider the effect of soil lateral displacement and to correct the constrained modulus due to the soil disturbance caused by PVD installation, respectively. The recommendations were provided after applying the proposed method to a case history.