Applied Mechanics and Materials Vols. 580-583

Abstract: Through the analysis of ‘gap parameter’ and ground movement pattern in shield tunnel, this paper researched and corrected the model of ‘equivalent circle zone’ proposed by predecessors. The ‘equivalent circle zone’, which is a comprehensive reflection of shield gap, grouting filling and stratum perturbation, is considered to be unequal thickness in this paper. With the measured data of practical shield tunneling, the unknown parameters of corrected ‘equivalent circle model’ can be obtained by back analysis through numbering analysis. The back analysis of Shen Zhen line-5 is carried out to validate the rationality of the method proposed in this paper. Research shows that: the corrected model can reflect the feature and values of ground settlement more factually than the previous model and can offer a reference to predict ground deformation during shield tunneling.

Abstract: A position conflict exists between Harbin Urban Rail Transit Line No.1 and the branch tunnel of "7381" civil air defense tunnel. Intense tunnel interaction occurs when Line No.1 is perpendicularly tunneled across the branch tunnel. The investigation of the interaction is necessary. A 3D numerical simulation is established using FLAC^3D and the vault deformation around the tunnel intersection is analyzed. The vault settlement of Line No.1 increases by 1.4 times during crosswise tunneling, while the vault settlement of branch tunnel increases 21.0mm in addition. The affected region of the tunnel intersection is further revealed. The affected length of the vault of Line No.1 and branch tunnel is 7.5 times the diameter and 6 times the width respectively. In combination with monitoring data, the reinforcement effect is studied at last. Both the vault settlement and surface settlement are well controlled in the tunnel intersection.

Abstract: Due to poor bonding of a shield machine main drive leading to seal failure sealing fracture failure occurs, the proposed installation forms of adhesive sealing method is replaced by platen method, and seal material NBR replaced by a fluorine rubber, so that the combination of the housing seal is more reliable, avoiding the fracture caused by discontinuity of local sealing. Construction process increases the injection of three different oils enhancing the sealing effect. Through the application of practical project, no failure appears after sealing transformation.

Abstract: With the rapid development of metro, the vibration induced by metro is the more and more common and widely concerned. In this paper, test and analysis of vibration induced by metro is discussed, and the five aspects of the research status at home and abroad are emphasized, which are the analysis of the vibration causes, the analysis of vibration influence, the summary of vibration test technology, the analysis of the relevant theoretical results and the analysis of vibration reduction application measures. This paper will provide the theory basis and the practice reference for the vibration design of environmental vibration induced by metro.

Abstract: According to the monitoring result of wall structure which its depth is over thousand, analyzed the strain of inner and outer edges of concrete and inner steel; Neglect construction factors, by comparing the strain of inner concrete and inner steel, it shows that their deformation is consistently; Using the average strain of inner and outer edges of concrete to check strength adopting method of concrete structure design code, shows that they can meet the requirement.

Abstract: This paper mainly deals with the structural design of high speed railway tunnel and its driving method in abrupt slope with loose rockmass, meanwhile summarizes the connection between tunnel portal and bridge abutment in loose rockmass according to complicated landform and geology. The anti-slide piles are adopted to retain the stability of abrupt slope near the tunnel portal. In order to eliminate the risk and cost in tunnel construction, four bench cut method is invented to satisfy the safe excavation of loose rockmass in the tunnel. Composite fiber rockbolt is also employed to keep the stability of working face while driving the tunnel. The innovative tunneling method presented in the paper can be applied to guide the rational design and economical construction of high speed railway tunnels in loose surrounding rock under harsh geological conditions.

Abstract: The thesis takes a three-lane tunnel construction in Zhejiang as an example. Simulating the course of dynamic construction of large-span tunnel on geology condition of four-grade rock mass and shallow buried by FLAC 3D software ,it carries out comparative and stress situation in the runnel surrounding rocks .Getting the displacement and stress changes rule of the construction by using benching with a small pilot tunnel tunneling method can guide the construction scientifically.

Abstract: Safety of secondary lining is of utmost importance to tunnel engineering quality as the main load-bearing structure and the last waterproof line of rock tunnel under type III. The comparative study of strain state results from FEM numerical simulation and on-site monitoring in Yunnan Tianxin Tunnel was conducted to obtain the stress regularity of tunnel lining. The results showed that except vault, the strain states of secondary lining obtained by numerical simulation and on-site monitoring were consistent. The strain value of on-site monitoring was approximately 60%~70% to the simulation value. And the strain value of right side was greater than the value of the corresponding location on the left side. It’s noticed that high strain were found in tunnel haunch and arch springing. Great attention should be paid to arch springing for the largest strain value. The strain monitoring value of vault (309.83με~327.23με) has been detected larger than simulation value (209.37με), which matches well the crack phenomenon of vault. Therefore it’s significant to focus on the long-term monitoring of vault. The defects of single on-site monitoring method such as poor predictability were made up effectively by comparative study. The results achieved can be recommended for similar projects.

Abstract: On the basis of hydrogeology data,Mohr-Coulomb constitutive model in software MIDAS GTS was employed to simulate excavation deep foundation pit in Qingnian Road station of Tianjin subway line 2 after each excavation step of different construction procedures.It is positive scinentifcity for simulating excavation pit ahead of time and predicting its deformation and displacement characteristics in the foundation pit,and it is significant for the timely revision of the schemes in the next construction process.

Abstract: The point load test and rebound tests were part of a simple rock testing methods, which together with a user-friendly, work environment characterized by less demanding test, so test the application of rock in the tunnel are very broad. Obtained by these two tests of rock uniaxial compressive strength Rc saturation level for the characterization of rock hard quantitative indicators, in the rock classification has a high status. With the computer technology in tunnel works in the field of application that can batch test data to establish the tunnel surrounding rock classification system. Article is based on two kinds of test in the same tunnel project in contrast to the use, through the rock classification system to analyze and evaluate both.