Tunnel Engineering Construction Research Articles

Investigation and practical application of a new cementitious anti-washout grouting material

The inrush water disaster seriously affects the construction of tunnel and underground engineering. In order to improve the efficiency of dynamic groundwater sealing in karst area, a new cementitious anti-washout grouting material (CIS) was prepared which consist of matrix material ordinary Portland cement, coagulant accelerator water glass and flocculating agent xanthan gum. The results show that CIS grout has the advantages of short setting time, high early mechanical strength, high slurry viscosity, high slurry retention rate and non-toxic, and it has the advantages over the cement-water glass slurry which is most widely used in the dynamic groundwater sealing engineering. The mechanism effect of water glass and xanthan gum on the workability of CIS grout was discussed by hardening process, X-Ray Diffraction (XRD), Mercury Intrusion Porosimetry (MIP), Infrared spectrum (IR) and Scanning Electron Microscope (SEM). A design method of grouting parameters was proposed based on the setting time and viscosity evolution, and the contrast application of CIS grout with cement-water glass grout was carried out in water inrush control project of limestone mine in Karst Area, and the water rushing was treated more effectively by CIS grout.

Analysis and Study on Crack Characteristics of Highway Tunnel Lining

Lining cracks are one of the most common diseases in highway tunnels, and the existence of lining cracks directly affects the overall stability and durability of tunnels, which has an important impact on the safe operation of tunnels, and it is necessary to analyze and study the characteristics of tunnel lining cracks. Combining with the detection data of multiple highway tunnels in the field, the different types of tunnel cracks are divided, and the classification numerical statistics method is used to obtain that the number and length of annular cracks in highway tunnel cracks are significantly higher than those of the other two kinds of cracks, and the longitudinal cracks in tunnel crack cracking degree are greater than the circumferential cracks and the inclinded cracks. The influence degree of cracks on the safety of tunnel structure longitudinal cracks are relatively the largest, the inclinded cracks are second only to longitudinal cracks, and the influence of cyclic cracks is relatively small. It provides reference for tunnel engineering design, construction, operation management and comprehensive improvement work.

Numerical Analysis of Surrounding Rock Stability in Super-Large Section Tunnel Based on Hydro-Mechanical Coupling Model

The groundwater seepage has an important effect on the stability of tunnel surrounding rock. Considering the effect of seepage, a hydro-mechanical coupling mathematical model is developed based on stress deformation equation of rock mass, flow equation of porous media and relation equation of hydro-mechanical coupling. In connection with the leakage situation of Jiangshuiquan Tunnel with super-large section, a geometry model of tunnel construction is built by COMSOL software platform. Furthermore, the hydro-mechanical coupling model is embedded in the PDE module of the software for numerical simulating the construction process of super-large section tunnel. Consequently, the surrounding rock displacement deformation under is discussed and verified by the data measured in field. Besides, the distribution characteristics of surrounding rock stress, seepage pressure and velocity are deeply analyzed. Results indicate that the displacement calculated by hydro-mechanical coupling model is well consistent with the site monitoring data and is greatly more than that of uncoupling model. After tunnel excavation, stress concentration phenomenon occurs around the cavern, especially at the arch foot part of the outer side wall, so the parts should be viewed as the key supporting part. The groundwater flows into the cavern and the surrounding pore water pressure is unloaded. A large hydraulic gradient occurs in the vault of the tunnel, prone to incur major engineering accidents; while the hydraulic gradient at vault is relatively small and usually has little harmful to engineering safety. The conclusion may provide guidelines for similar tunnel engineering construction.

Study of the Corrosion Characteristics of Tunnel Fissures in a Karst Area in Southwest China

The development of the fissures in soluble rock of karst areas directly affects the construction and operation safety of tunnel engineering. It is thus of theoretical and practical significance to study the characteristics of its corrosion and its influencing factors. Taking the Wulong tunnel as the research object, the numerical model of the study area was established to quantitatively analyze the corrosion range, corrosion ratio, and changes in the permeability and porosity of the fissures in soluble rock of karst areas of the tunnel over the past 100 years, and the simulation results were verified by field experiments. The results show that the main controlling factor of the fissure corrosion of the tunnel in the karst area is the flow rate. The corrosion range and corrosion ratio of the fissures of the tunnels in the karst area increased with temperature because the reaction rate constant increased with temperature, causing the reactions’ equilibrium to move towards the direction of the solution. The larger the initial permeability and the larger the porosity of the fissures, the faster the fissures corrode. In the same time period, the fissures with high permeability and large porosity will lead to the permeability and porosity being more enhanced, thus causing the corrosion of the fissures to exhibit secondary enhancement effects. The opening of the dead-end pores greatly enhanced the permeability and slightly increased the porosity, which caused the differential corrosion of fissures in the karst area. The protection of the tunnel should be strengthened, mainly in strong hydrodynamic conditions and in the fracture development zone.

Research on he Classification of Life-Cycle Safety Monitoring Levels of Subsea Tunnels

Abstract As a traffic engineering project across straits or gulfs, subsea tunnel is one of the oceaneering with great construction difficulties, and the key to the success of subsea tunnel engineering lies in timely and accurate assessment of the structure safety of subsea tunnel engineering construction and life-cycle. Xiang’an Xiamen subsea tunnel is China’s first subsea tunnel which crosses complex formation conditions, engineering accidents such as collapse, sudden inflow of water or mud might occur during tunnel construction and operation. Therefore, the concept of subsea tunnel life-cycle monitoring is proposed aiming at the particularity of subsea tunnels. The variation forms of subsea tunnel mainly include large deformation, collapse, primary support cracking, water leakage, water pressure increase, steel arch corrosion, concrete corrosion, longitudinal differential settlement, etc., and classification of the life-cycle safety monitoring levels of the subsea tunnel is conducted based on risk assessment theory and risk level management benchmark to determine the possible variation forms in the monitoring level segments. The research results will provide reference for the subsea tunnel life-cycle monitoring, disaster warning as well as risk management under construction or to be built at home and abroad.

Study on Comprehensive Monitoring Tech-nology of Highway Tunnel Construction

In recent years, China has made great progress in highway construction. Its scale and mileage have been expanded. The development of highway tunnel construction has become very rapid. In the mountains and cities, tunnels have become more and more important.To do a good job of highway tunnel construction control work, to take scien-tific monitoring technology can quickly and accurately obtain the measurement information, for the specific construc-tion to give some guidance. So it is necessary to study the new monitoring technology in the construction of tunnel en-gineering. Therefore the article analyzes the comprehensive monitoring technology of highway tunnel construction.

The Dynamic Response of Tunnel through the Karst Cave under Impact Load

More and more construction of tunnel engineering in karst region. Karst influence on tunnel engineering in deformation and instability, it often leading to Partial collapse, impellers, rock fall in the tunnel excavation or after work. For through large Karst cave tunnel, it will give great harm to tunnel, adjacent structures and injuries and consequence is very serious when faced with karst collapse occurs. The paper is based on engineering example of XieGiadong cave tunnel, the research results has important value for engineering construction and protection of resources. For example, the tunnel lining structure under the action of impact load produced large deformation and the overall shear failure and the process is ephemeral. Tunnel in the process of impact contact to destroy only less than 0.1 S, The vertical displacement of 2.88 m, the horizontal displacement of 0.8 m, fall since the collapse of rock mass to the maximum contact force of the contact with the tunnel 7000000KN.

Analysis of the Engineering Geology and Deformation Control in Highway Tunnel

The tunnel engineering geology and deformation control is one key of the basis for the tunnel engineering construction and operation management and safety technology security. However, it is becoming one of the bottleneck problems for underground tunnel construction project information to be solved accurately and fast to assess the stability of surrounding rock because of the special environment in the tunnel construction and acquiring the deformation information of surrounding rock. Relying on the geology analysis and the surrounding rock deformation control of research work on the ZIJING mountain tunnel in DAGUANGNAN highway in HUBEI province of Chinese, it is investigated to combine the geological information with field monitoring organically which is in order to determine the possible geological damage during tunnel construction. Then, based on the monitoring data processing and analysis, the deformation control standard of the tunnel geological disaster area is putted forward. Those research works are providing important reference basis for similar projects.

The Comparison of Tunnel Engineering Construction Methods for Renhechang Tunnel Crossing Underneath Existing Tunnel on Lanzhou-Chongqing Railway

Problems often exist in construction of transportation tunnels, such as the effect of new tunnels constructed close to existing structures. Solving this magnificent problem by carefully choosing tunnel construction methods will be beneficial to minimize effects on existing structures while ensuring the newly constructed tunnel is both time-consuming and economical. Three representative engineering methods-the benching tunneling method, the Center Diaphragm method and the Cross Diaphragm method-are compared in controlling the settlement of new tunnel vault and the deformation of the existing tunnel. Finally checking the simulation results by comparing with field measurement data.

Effect of Cross Passage Construction on the Structural Safety of Collapse Reinforcement Segment of Existing Tunnel

On the basis of the engineering background of cross passage construction in the Chen Yu Tunnel project, the collapse section above the intersection of the existing tunnel is selected to establish finite element model. Considering the effect of cross passage construction and the local weakening area of surrounding rock on the safety of existing tunnel structure, the strength of the shotcrete supporting structure of existing tunnel intersection is checked, and the security of the existing tunnel is evaluated. This research is of great practical significance and a certain reference value for the plan and design upon the construction of tunnel engineering.

Risk Evaluation of Highway Tunnel Construction Based on DEMATEL Method

According to the correlation characteristics of risk factors in highway tunnel engineering construction, based on the risk identification and analysis of accidents, the interactive correlations among these risk factors are analyzed by Delphi Method. This paper adopts the decision making trial and evaluation laboratory (DEMATEL) method to analyze the risk of tunnel engineering construction. Then, a comprehensive influencing coefficient of various risk factors is calculated by a comprehensive influencing matrix, the reason-result chart for these risk factors is made, and the key risk factor influencing the tunnel engineering construction is obtained. The result shows that DEMATEL method is effective for the risk analysis of tunnel engineering construction via the case study of Wulong Tunnel construction in China.

Numerical Simulation of Advanced Small Pipe in Tunnels during Excavation by Steps

Advanced small pipe support is one of the advanced support patterns in tunnel engineering construction for weak and fractured surrounding rock. The support effect cannot be predicted because of depending on engineering experiences. Efforts are made to study and analyze the support mechanism of advanced small pipe in the excavation of soft - fracture wall rock. By the numerical simulation of FLAC3D of Dawangou tunnel based on rock mass deterioration model (RDM), the plastic zone, displacement and stress filed of the surrounding rock are simulated with and without the advanced small pipe support. The support effect of advanced small ducts in tunnels during excavation by steps is presented.

Developing and Applying the Information Construction Analysis Visualization System

Tunnel information construction is more and more concerned because of the uncertainty and complexity of geological body. Based on the back analysis principle of tunnel and intelligent science arithmetic, the paper self-developed tunnel information construction analysis visualization system by Visual C# platform and VTK techniques in order to the confliction between tunnel construction expending too much time and the construction period demand. Firstly introduced global optimization method-Difference Evolution (DE) Algorithm and combined it with finite element method (FEM) in order to back analyze the surrounding rock parameters. Then constructed the total software framework and developed the program of the information construction analysis intelligent visualization system. Applied the system to the Dalian Metro tunnel engineering construction and got satisfied results. The soft system developed by the paper has active meaning to promote the intelligence, visualization and automation of the tunnel construction.

Preliminary Study of the Geological Disaster Modeling in the Three-Dimensional Tunnel Project

There are various potential natural geological disasters in the process of tunnel construction, such as methane gas, tunnel collapse, tunnel gushing, etc. Due to the limited data collection and the invisibility of some natural phenomenon, how to simulate these geological disasters more visually and increase its early warning management more effectively has been a tough problem in three-dimensional simulation. This paper briefly describes the GIS-based three-dimensional rendering technology and the feature attribute management method to achieve the geological disasters modeling in the tunnel and its simulated prediction, which can provide auxiliary support for the decision of the safe construction of tunnel engineering.

Tunnel Support Parameters Optimization Based on Micro-Seismic Monitoring

The monitoring is important to keep tunnel engineering construction stability. But, regular monitoring means cannot detect the position of the rock which has much stress accurately, accordingly, cannot monitor the influence of the construction process. In order to detect the local surrounding rock cracking due to excavation, a new method named micro-seismic monitoring is proposed to identify the elastic wave of rock bursting. Micro-seismic monitoring technology can find the bursting position by use the elastic wave of the rock, then, it can make an evaluation about the stability of the rock. In the method, using several sensors monitoring data of elastic wave identifies the bursting location. Then, the stability of the rock is analyzed and tunnel support parameters are optimized. At last, the method is used to monitor the Yuanyanghui tunnel located in Shanxi Province, China. The monitoring results identified the relatively stable and relatively unstable area. In-situ measurements on the surrounding rock have been used in the two areas, and therefore we use the analysis results to improve the initial tunnel support parameters.

Numerical Simulation for Large Section Tunnel Based on Stress Mapping Return Arithmetic and Loading Releasing Method

Aiming at that general Finite Element Method is difficult to simulate the complex tunnel excavation inducing the second stresses adjusting, the paper proposed the simulation methods combining loading releasing and stress mapping return arithmetic. After the introduction of relative theory, the FEM code has been developed by VC++ . The excavation process of a large section tunnel engineering CRD construction is simulated by the code, the displacements contour, arc top and arc shoulder settlement, horizontal convergence and ground face settlement corresponding to each excavate step have been obtained by the simulation. The regulation of the results are compared with monitoring data, which stated the method is feasible. The simulation has guiding meaning to the tunnel engineering construction.

Model Test and Numerical Simulation for Support Time of Tunnel in Loess

The work presented in this paper focuses on support time for tunnel, which has much effect on stability of tunnel. Based on loess tunnel of Zhengzhou-Xi’an high-speed passenger rail line in China, large scale model test with geometric proportion 1: 20 was applied to study on different support time. Supplemental numerical analysis was carried out to investigate the effect of release ratio of stress which cannot be covered by model test. It is revealed that it is asynchronous change for deformation, strain and stress of surround rock. If the supporting constructs prematurely, internal force of support would be excessive greatly and if the supporting constructs too late, it will bring excessive slack pressure which leads to the plastic zone unfavorable, even tunnel collapse. The reasonable support time can improve self-bearing capability of surrounding rock and reduce the cost. The limited displacements about 17.8 cm for crown and 12.9 for horizontal convergence are gained. The research results can act as reference for similar materials tunnel and underground engineering construction.

Model test for dynamic construction mechanical effect of large-span loess tunnel

It has been a focus of debate for a large time on construction methods for large-span loess tunnel. Reasonable construction method has much effect on stability of tunnel and construction schedule. Deformation and failure of surrounding rock are quite complex. Associating with the large-span loess tunnel of Zhengzhou—Xi’an high-speed passenger rail line in China, large scale model test with geometric proportion 1:20 is applied to study on dynamic mechanical behavior of various construction methods. They include full-face excavation with support and no support, and benching method with support. It is found that pre-deformation and stress accumulation take place ahead of working face. The effects of three construction methods are further studied, particularly in terms of tunnel displacement and stress changes. It is revealed that benching method transfers load to an unexcavated area, limits horizontal deformation, reduces stress concentration effectively, lengthens the distance between location of peak for stress concentration and working face, and consequently increases stability. The model test results not only supply theoretical foundation for determination of reasonable construction method, but also can act as reference for similar tunnel and underground engineering construction.

Study and Application of Forecasting System for Water Inrush Under High Pressure in Xiamen Submarine Tunnel Construction Based on GIS

Abstract To ensure the project safety of Xiamen submarine tunnel, it's necessary to study the risk of water inrush under high pressure to provide a reference for prevention and control measures. With the support of GIS software, a forecasting system for water inrush in Xiamen submarine tunnel was researched and developed, which realized the automated process from basic data input to the result assessment of water inrush. The technical route was that the results of numerical simulation have been evaluated by professional model. The findings of the evaluation have been regarded as its background database which has been updated with real-time geological data and groundwater data during the tunnel construction. The forecasting system has been studied by simulation tools of FLAC 3D, MAPGIS as its basic platform and VC++ as the developing tool. System functions include data input and output, data query, water inrush forecasting and result display function. The application of this system in Xiamen submarine tunnel engineering construction indicates that the system can provide a relatively correct engineering guarantee for water detection in safe tunnel excavation.

Research on the Evaluation of the Tunnel Leakage Classification Based on BP Artificial Network

Tunnel Leakage has been a key issue of the Tunnel Engineering construction and maintenance because of the universality and serious harmfulness. Aiming at the status of tunnel Leakage in our country, this paper identifies the main factor from all kinds of factors. An evaluation indexes system is advanced which consists of 10 factors coming from following four grade indexes, including construction factors, Drainage and Waterproof Methods for Waterproof Tunnel, the situation of Surrounding Rock and groundwater and physical geography. In addition, an evaluation model based on the BP artificial network is designed. Combining with evaluation example, the calculation method is realized by software. The results show that the evaluation method is useful. The method provides a new way to increase the precision of tunnel leakage disease level evaluation.