Advancing Control for Shield Tunneling Machine by Backstepping Design with LuGre Friction Model

Shield tunneling machine is widely applied for underground tunnel construction. The shield machine is a complex machine with large momentum and ultralow advancing speed. The working condition underground is rather complicated and unpredictable, and brings big trouble in controlling the advancing speed. This paper focused on the advancing motion control on desired tunnel axis. A three-state dynamic model was established with considering unknown front face earth pressure force and unknown friction force. LuGre friction model was introduced to describe the friction force. Backstepping design was then proposed to make tracking error converge to zero. To have a comparison study, controller without LuGre model was designed. Tracking simulations of speed regulations and simulations when front face earth pressure changed were carried out to show the transient performances of the proposed controller. The results indicated that the controller had good tracking performance even under changing geological conditions. Experiments of speed regulations were carried out to have validations of the controllers

Objectivation of the Necessity of Structural and Parametric Synthesis of the Hydraulic Drive Of Geokhod

This article considers main systems of a prototype model of geokhod as well as their technical specifications. There are ways distinguished of decreasing the dimensions and the mass of elements of the hydraulic drive. As an optimization tool of structural and parametric parameters of the prototype model of geokhod, there is SimHydraulic simulation considered

Advanced Underground Space Technology

The recent development of underground space technology makes underground space a potential and feasible solution to climate change, energy shortages, the growing population, and the demands on urban space. Advances in material science, information technology, and computer science incorporating traditional geotechnical engineering have been extensively applied to sustainable and resilient underground space applications. The aim of this Special Issue, entitled “Advanced Underground Space Technology”, is to gather original fundamental and applied research related to the design, construction, and maintenance of underground space

Study of the shear strength evolution over time of two-component backfilling grout in shield tunnelling

The two-component backfilling system is the most commonly used method to fill the annular void created during the advancement of shield machines. This unavoidable void, strictly linked to the technology of shield machines, must be filled continuously in order to avoid mostly surface displacements and lining movements. Today, this technology is the most frequently used due to operative and technical advantages, which lead to economic savings. However, despite intensive use of this backfilling technology, very little information is currently available concerning the evolution of the material in function of the curing time. Historically, the uniaxial compressive strength has been used as the main parameter for testing the compliance of a certain grout with the site-specific technical requirements, but nowadays shear strength is also starting to be considered by designers even if this topic has never been investigated. In this work, a laboratory test campaign focused on shear strength and its evolution in function of curing was performed. These tests put alight the fast mechanical growing of the twocomponent grout from the shear strength point of view and it should be remarked that at the current state of research there are no investigations concerning the shear strength in the context of a drainage approach. Both short and long curing times were investigated according to the direct shear test, performed under drained conditions. The Mohr-Coulomb failure envelope model was selected for the study and its widening in time highlights the peculiarity of this technology. Starting from a liquid phase at t0, values of cohesion (c') and friction angle (phi') grow in function of curing, reaching 126 kPa and 22 degrees at 3 h and exceeding 270 kPa and 40 degrees at 28 days

On the Effect of Shield Friction in Hard Rock TBM Excavation

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Proceedings of the 8th International Conference on Civil Engineering

This open access book is a collection of accepted papers from the 8th International Conference on Civil Engineering (ICCE2021). Researchers and engineers have discussed and presented around three major topics, i.e., construction and structural mechanics, building materials, and transportation and traffic. The content provide new ideas and practical experiences for both scientists and professionals

Proceedings of the 8th International Conference on Civil Engineering

This open access book is a collection of accepted papers from the 8th International Conference on Civil Engineering (ICCE2021). Researchers and engineers have discussed and presented around three major topics, i.e., construction and structural mechanics, building materials, and transportation and traffic. The content provide new ideas and practical experiences for both scientists and professionals

Flexural Behaviour of Steel Fibre Reinforced Concrete Tunnel Linings

The promotion of steel fibre reinforced concrete (SFRC) as a construction material for tunnel linings has prompted a number of researchers to focus on methods of evaluating their flexural strength and stiffness. This thesis presents the results of an experimental and numerical investigation of the flexural behaviour of full-scale steel fibre reinforced concrete tunnel lining segments. A series of a three-point flexure tests were performed to evaluate the maximum load carrying capacity, the load-deformation behaviour and crack propagation characteristics of these segments. The material properties of the steel fibre reinforced concrete were also studied, using both destructive and non-destructive methods. Element compression and tension tests were conducted to characterize the compressive and tensile strength properties of the SFRC. Additionally, computed tomographic scanning was conducted to analyse and estimate the density fraction and fibre orientation of the fibres in SFRC cores. Three-dimensional finite element analyses were conducted to calibrate a concrete damage plasticity constitutive model and provide better understanding of the segment flexural behaviour. The experimental program indicated that the variation in structural performance of the segments was likely due to an inhomogeneity of fibre distribution and orientation. Modifying the numerical model to account for these variations resulted in a more accurate analysis. Furthermore, from the numerical finite element analysis it was found that the non-linear elasto-plastic concrete damage plasticity model in the crack zone of the beam was mesh dependent. Parametric analyses also revealed that the model was particularly sensitive to small changes to the tensile material property input parameters