The settlement of thick backfill sand foundation in phase I of Yangshan deepwater seaport project is calculated by specification and one-dimensional consolidation theory. Based on layered settlement data measured in field,compressibility modulus and consolidation coefficient of soil layers are obtained by back analysis method,and thus the post-construction settlement of the foundation is predicted.
Relying on the trial lot of retaining wall reinforced with geosynthetics in a project at PuXi, Quanzhou, according to the analysis on the measured data of settlement, layered settlement, pore water pressure, lateral displacement and soil pressure, the paper studies the role and mechanism of geosynthetics in the reinforced wall, and the designing method is also discussed.
In-situ geotechnical monitoring and observation is of great significance to guide construction and ensure the quality of projects. Taking CJG-86 type extensometers and CJH-88 type magnetic cores, the layered settlement test was performed in the east road around Zhengzhou City (G107 Auxiliary Road). The distributing law of layered settlement was obtained, which can provide theoretical basis to staff members related to the design and construction of highway engineering.
The main research work in the paper is list as followed:1. Static load test for single pile and single pile composite foundation in tentative segment selected are made. Result of in-site tests, include surface settlement, settlement in layers, excess pore water pressure, stress in soil between piles, pile shaft stress, are analyzed.
Taking some test engineering of soft ground for example, this paper introduces the design thinking of cement powder-spray pile treating weak subgrade and the observation way of settlement in layers, analyses the experimental results, and thinks that there are good results.
On the basis of measured data this paper deals with changes in pore water pressure,ground subsidence and layering subsidence with time and constuction during stacking precompaction and soft ground treatment.
It is demonstrated that the post-construction settlements of the treated backfill sands at almost all the sequence settlement measurement points of Yangshan deepwater seaport are all less than 60 mm,those of untreated backfill sand and subsoil are all less than 300 mm,and that the post-construction settlement is mostly caused by the compression of the untreated backfill sand and subsoil,which consists of 80.90%～88.19% total post-construction settlement.