Large-scale model test study on the water pressure resistance of construction joints of karst tunnel linings

Model tests and numerical calculations were adopted based on the New Yuanliangshan tunnel project to investigate the water pressure resistance of lining construction joints in high-pressure and water-rich karst tunnels.A large-scale model test was designed and conducted,innovatively transforming the external water pressure of the lining construction joint into internal water pressure.The effects of the embedded position and waterstop type on the water pressure resistance of the construction joint were analyzed,and the reliability of the model test was verified via numerical calculations.The results show that using waterstops can significantly improve the water pressure resistance of lining construction joints.The water pressure resistance of the lining construction joint is positively correlated with the lining thickness and embedded depth of the waterstop.In addition,the type of waterstop significantly influences the water pressure resistance of lining construction joints.The test results show that the water pressure resistance of the embedded transverse reinforced waterstop is similar to that of the steel plate waterstop,and both have more advantages than the rubber waterstop.The water pressure resistance of the construction joint determined via numerical calculations is similar to the model test results,indicating that the model test results have high accuracy and reliability.This study provides a reference for similar projects and has wide applications.

All-out Startup of Construction of Sino-Kuwait Integrated Refining/Petrochemical Joint Venture Project

On December 20,2016 the construction of the SinoKuwait Guangdong integrated refining/chemical join venture project,which is the largest Sinopec’s projec under construction and also the key construction project of Guangdong province,had been kicked off comprehensively.This project is located in the new district of the East Sea Island inside the Zhanjiang Economic Development

Numerical analysis of dislocations of the face slabs of the Zipingpu Concrete Faced Rockfill Dam during the Wenchuan earthquake

The Zipingpu Concrete Faced Rockfill Dam （CFRD） was obviously damaged during the Wenchuan earthquake in 2008. A wide range of dislocations occurred along the horizontal construction joints at EL. 845m, between the face slabs constructed in the second and third stages. The maximum displacement of the dislocations reached 17cm. In this study, the slab dislocations were investigated using finite element （FE） analysis. The method based on strain potential was applied to compute the permanent deformation of the Zipingpu Dam during the Wenchuan earthquake. The calculated magnitude of the slab dislocation showed good agreements with the field measurements. The dislocation mechanism was discussed. The results show that the dislocation of the concrete slab is a subsequent damage after the permanent deformation of the rockfill materials. The effects of the shear strength and the direction of the construction joints, the reservoir water level and the seismic waves were studied. The shear strength and the direction of the construction joints, reservoir water level and have a significant effect on the dislocation displacement. The dislocation can be effectively reduced by measures such as changing the direction of the construction joints or improving the shear strength at the horizontal joints.

Numerical evaluation of segmental tunnel lining with voids in outside backfill

This paper presents a numerical investigation of the mechanical behaviour of segmental linings owing to the existence of voids in the composite lining.The composite lining was formed by mining outside and shield tunnelling inside with backfill in between.Finite element method was conducted to analyse the axial forces and bending moment for voids of different diameters at different positions.The results show that the axial forces in the transverse section increase near the crown and then invert and decrease on the left and right sides with an increase in the void centre angle(β)measured from the vertical axis.The increase in void diameter(d<300 mm)induces an increase in the axial force on the left and right sides when β=45°and 90°,while it decreases near the crown and invert.The occurrence of voids leads to an increase in the bending moment in the entire segment section with an angle β.