Most geotextiles consist of polymers of polyolefin, polyester or polyamide family, which involve environmental problems related to soil pollution. Geotextiles can be used for at least one of the following functions: Separation, reinforcement, filtration, drainage, stabilization, barrier, and erosion protection. Due to the characteristics of high strength, low cost, and easy to use, geotextiles are widely used in geotechnical engineering such as soft foundation reinforcement, slope protection, and drainage system. This paper reviews composition and function of geotextiles in geotechnical engineering. In addition, based on literatures including the most recent data, the discussion turns to recent development of geotextiles, with emphasis on green geotextiles, intelligent geotextiles, and high-performance geotextiles. The present situation of these new geotextiles and their application in geotechnical engineering are reviewed.

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Shield tunneling adjacent to pile groups is always an unavoidable problem in urban metro construction. A case was found in the project of Tianjin Metro Line 7, where a shield tunnel would be constructed near the existing pile groups of Shiyou Bridge. The whole shield tunnel is close to pile groups, and the minimum distance is only 0.8 m. Therefore, four kinds of protective schemes are proposed in this paper. It is vital to select an appropriate protective scheme to guarantee the safety during the tunnel construction. In this study, the main mechanical characteristic and physical parameters of site soil were obtained through laboratory tests. Besides, the three-dimensional finite element method was carried out to compare and analyze the effectiveness of the protective schemes in mitigating the effects of tunneling on adjacent pile groups. The results show that the deep-hole grouting scheme has better control effect on the lateral deformation and bending moment of piles, while the pile foundation underpinning scheme has better effectiveness on reducing the settlement of bridge structure and ground deformation. Finally, the deep-hole grouting reinforcement scheme will be adopted to ensure the shield passing through the pile groups smoothly.

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Referring to CATIA's 'assemblies + parts' modeling method, CATIA-based BIM (Building Information Modeling) technology has been proposed for highway tunnel design in this paper. A tunnel BIM is created by CATIA, which is based on a real case in China, focusing on the following 3 aspects: (1) Creating tunnel bolts by UDF + Loop cyclic arrangement method; (2) Using Sketch Tracer module to create tunnel portal; (3) Parameter is used to create and call the Catalog database. Then, bolt collision inspection and U-shaped groove concrete statistics are conducted with the help of the tunnel BIM created. Finally, the finite element analysis of tunnel construction process is carried out through the CATIA-Midas interface. The results demonstrate that the CATIAbased BIM technology can well adapt to the characteristics of tunnel and have well potential applications in tunnel design.