Search

The MRT Orange Line construction works in Bangkok are more complicated than works in earlier projects. As the tunnel alignment passes through the congested urban areas in the city, it either clashes with or passes beneath several existing structures. Underpinning works are then required. Assessment of movement of ground and structure plays an important role in the project. The rebound of piezometric pressure in sand layers that is being developed poses a major point of difficulty in the excavation and underground structure design and construction. Groundwater control measures become a crucial issue in MRT Orange Line project that leads to difficulties in deep MRT station excavations. To control base instability, various methods (e.g., cut‐off wall, staged excavation) are introduced and presented in this article. [ABSTRACT FROM AUTHOR]

A building and its foundation were constructed in sandy ground using a reverse construction method. The main difference between a reverse construction method and a conventional construction method is that the piles are cast in place and are partially loaded by the superstructure early during the construction process. It is only later that the raft (mat foundation) is constructed to combine with the piles to bear the full building load. Therefore, the foundation is regarded as a pile group in early stages of construction, while the foundation behaves as a piled raft after completion of the raft construction. A simple conservative design approach was used for the design of the foundation. To examine the validity of the design method, settlements of the foundation were observed during construction. The measured settlements were smaller than those predicted in the design stage, satisfying the design requirements for the building. Post-analysis of the deformation of the foundation was carried out using the results of the pile load test at the construction site, and the results of the analysis are compared with the observed settlements of the foundation, aiming at an improvement in pile foundation design. Key words: piled raft, vertical pile load test, reverse construction method, deformation analysis, water pressure, sandy ground. Un batiment et ses fondations ont ete construits sur un sol sablonneux selon la methode de construction inverse. La difference principale entre la methode de construction inverse et la methode de construction traditionnelle est que les pieux sont installes et partiellement charges par la superstructure au debut de la construction. Ce n'est que plus tard que le radier (tapis de fondation) est construit et combine aux pieux pour soutenir toute la charge du batiment. Ainsi, la fondation est consideree comme un groupe de pieux au debut de la construction, alors que la fondation se comporte plutot comme un radier sur pieux une fois le radier construit. Une approche simple et conservatrice a ete utilisee pour la conception de la fondation. Afin d'evaluer la validite de la methode de conception, le tassement des fondations a ete observee durant la periode de construction. Les tassements mesures etaient plus faibles que ceux predits a 1'etape de conception, ce qui correspond aux exigences de construction du batiment. Une analyse de la deformation des fondations a ete effectuee ... partir de resultats d'essais de chargement sur les pieux au site de construction; les resultats de cette analyse ont ete compares avec les resultats d'observations de tassement des fondations, ceci dans le but d'ameliorer la conception de fondations sur pieux. Mots-cles : radier sur pieux, essais de chargement vertical sur pieux, methode de construction inverse, analyse de deformation, pression d'eau, sol sablonneux. [Traduit par la Redaction], Introduction In many countries (except for Germany), most pile foundations for buildings are still designed as pile groups, in which the contribution of the raft resistance is ignored even though [...]

This study focused on the investigation of influencing factors on behaviour of piled raft foundation in Bangkok subsoil. To evaluate the possibility of implementing this system in Bangkok subsoil condition, this research performed the consolidation analysis of piled raft foundation systems for low-rise (8- storey) and high-rise (25-storey) buildings with basement levels in clay soil, using coupled three-dimensional (3D) mechanical and hydraulic numerical model. The soils are modelled with Hardening Soil model and Mohr-Coulomb model. Evaluations of piled raft foundation, i.e., the load sharing ratio of piles, settlement behaviours in the foundation system are performed. The parametric study on the effect of raft depth, and load carried by piles of piled raft was done. The consolidation had a strong influence on the load carried by piles of the piled raft foundation in Bangkok. The load shared by piles can increase by up to 12% and 6% for low rise and high-rise buildings, respectively due to the consolidation effect. Therefore, the design of the piled raft foundation system in Bangkok subsoil essentially consider the consolidation effect. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)