In this paper, based on an actual pit excavation project, the mechanical process of excavating and retaining is simulated. Combined with the monitoring data, the stress, displacement of soil and internal force of retaining structures are analyzed, and the characteristics of deformation and force are summarized. This research offers references for safe and economical design and construction, and helps to improve the design theory of foundation pit support.

During the maintenance of a free-flow tunnel built in a water-rich area,severe cracks of the concrete lining with continuous disengagement between both the lining and the surrounding rock are found;for which,the seepage and stress field around the tunnel are simulated herein with the 3-D finite element method in accordance with variation process of the seepage field.The result shows that the external water pressure is possibly to be the cause of the cracking.Therefore,the relevant treatment measures and suggestions of lowering the external water pressure and tension stress of the lining are put forward.The in situ observation shows that the calculation scheme given herein and the results are reasonable.

Eccentrically braced steel frame is a good anti-seismic structure which can be used in seismic area. A series of experiments and theoretical researches have been conducted in developed countries. However, research on this kind of structure in China is at an early stage. This paper reviews experimental, theoretical and practical application researches in China. The aim is to contribute to a better understanding of the development of the structure for designers in China, to provide a reference for researchers in this area, and to accelerate practical usage of the structure in seismic areas.

Taking the gate-dam for Doutankou Hydropower Station on Niulanjiang River as a study case,the 3-D seepage field and stress field for this kind of structure pattern for the gate dam constructed on a pile foundation with deep over burden under several operation conditions are analyzed herein.As the horizontal thrust on the dam body,horizontal seepage force on the dam foundation and vertical seepage pressure on the dam bottom caused by the large water depth in front of the dam and the high permeability of the strata therein are greater,larger horizontal displacements of both the dam body and the pile foundation occurred.Therefore,the measures to reduce the horizontal displacements are comparatively studied;in which a foundation treatment scheme of combined load bearing with both the pile foundation and the foundation anti-sliding wall for the gate-dam is put forward for the first time.

This paper analyses a tunnel being dug below the underground channel with a three-dimensional finite element analysis method,considering its non flexible structure properties and its structural joint existence.The step by step excavation,the advance reinforcement,the preliminary bracing and the construction near the existing structure processes are simulated using the 3-D FEM.The process shows that we can get the more exact solution close to the practice project on the structure settlement and stress with the method,thus provides a more accurate basis for the tunnel structural design.The analysis also indicates that the settlements between the ground surface of the top underground channel and the bottom plate are rarely small.Evaluation of the underground channel safety can be based on the tensile stress increment of its bottom plate,referring the tunnel stress condition before the excavation of the underground channel at the same time.

Many hydropower stations are planned and being constructed in high seismic intensity zones in China.When the great earthquake strikes,lots of ground factory buildings are ruined and thousands of people are killed,which is awfully shocked.The seismic design of hydropower plant building located in high seismic intensity zone is focused on by engineers.In this paper,the Xiaoqinghe hydropower station bank plant house which will be constructed in grade 9 seismic fortification intensity zone is analyzed with the 3-dimensional Finite Element Method.The building’s structure is analyzed and checked in 4 load cases of structure adjustment and different seismic intensity earthquakes.The analysis procedure and conclusions of this paper offers a valuable reference to the same kind of projects.

Multi-body model of a 3-RRC parallel robot is built and Kinematic simulation is carried out based on the software ADAMS.Through the measuring tools and spline function,the direct kinematics solution of 3-RRC parallel robot is worked out.It is proved that the direct kinematics solution method of 3-RRC parallel Robot presented is effective and rapid.

The Beijing Hui-nan-zhuang pumping station of the South-to-North Water Diversion Project Mid-route is a large-scale project with high engineering quality demands.In this paper the forebay is analyzed with the 3-D FEM.Many load cases are considered simulate the construction,service and seismic responses etc.The analysis results and conclusions are valuable for design and construction,and also can be references for similar projects.

In this paper,the tunnels construction adjacent to existing pile foundation is studied.Two water diversion tunnels are embedded in soft ground under road.The construction process of tunnels adjacent to bored piles is simulated with the 3-D nonlinear finite element method in details,considering the materials properties change with time.The conclusions and suggestions are valuable for the engineering design,and worthful as references for the similar projects.

Based on the incremental elastoplastic theory,the construction of 2 water transfer tunnels and the gallery are simulated by the 3-D fi- nite element method.The tunnels and gallery are excavated in gravel layer under the west Beijing Fourth Loop Road.The excavation and support process are analyzed in five construction cases in details,considering the materials properties change with time.Comparing with the construction survey data,the results prove reliable.The conclusions and suggestions are helpful for the engineering design of the similar projects.

In this paper,the tunnels construction adjacent to existing pile foundation is studied.Two water diversion tunnels are embedded in soft soil under road.The construction process of tunnels adjacent to caisson piles is simulated with the 3-D nonlinear finite element method in details,considering the materials properties change by time.The conclusions and suggestions are valuable for the engineering design,and worthful as references for the similar projects.

The eccentrically braced steel frames(EBSF) are a new structural system based on the concentrically braced frames,which improves the seismic performance of the steel frames under the earthquake.An improved model of the link beam of the EBSF has been proposed in this paper.The dissipative principles and characteristics of the EBSF have been analyzed based on this model,considering both the strain hardening effect and the interactive action between the bending moment and the shear force.Three different types of EBSF have been analyzed using this method in order to get their plastic performance as well as their plastic design under the earthquake.