3D numerical parametric study of the influence of open-pit mining sequence on existing tunnels

Beyabanaki, Amir Reza; Gall, Vojtech

doi:10.1016/j.ijmst.2017.03.018

Cited by 20 publications

(9 citation statements)

References 26 publications

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“…However, the existing evaluation methods of surrounding rock stability are difficult to meet correctly the requirements from tunnel designing and construction due to the low precision and maneuver ability in the majority of real criterions, and it is difficult to carry out in practical tunnel engineering. In the analytical method, plastic region, tensile region, damaged region, maximum tensile stress, and displacement of tunnel surrounding rock mass are usually used as the stability index of tunnel surrounding rock mass [9][10][11], but some of indexes are difficult to obtain around tunnel during construction phase, such as plastic region, maximum tensile stress, and strain. e displacement of tunnel surrounding rock mass, which is easy relative to monitor on construction site by traditional monitoring method or last noncontact method, is selected as the index of tunnel surrounding rock stability [12][13][14].…”

Section: Introductionmentioning

confidence: 99%

An Analytical Calculation Method for Displacement Criterion on Tunnel Surrounding Rock Mass Stability

Zhang

Chen

et al. 2022

Advances in Civil Engineering

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Assessment on the stability of a tunnel surrounding rock mass is an important issue during designing and construction of the tunnel. There is still no good enough analytical method to calculate the displacement criterion on the stability of the tunnel surrounding rock mass due to its multifactors dominated. In this paper, an innovative method to achieve the assessment displacement criterion, based on elastoplastic theory, is formed by considering multifactors, such as the quality of surrounding rock mass, initial stress, tunnel size, and supporting system. The calculation formula in this method is deduced by taking into consideration of combination the displacement and plastic region of surrounding rock mass and the reinforcement zone by systemic bolt, based on the equilibrium in elastic region, plastic region, and border between elastic region and plastic region. Furthermore, the influence of critical factors on the displacement criterion, such as deformation property and strength property of surrounding rock mass, tunnel size, and tunnel overburden, is discussed to make it clear that how these factors affect the stability of the tunnel surrounding rock mass. The validity of the analytical calculation method is testified by the application in the Zipingpu tunnel engineering.

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Section: Introductionmentioning

confidence: 99%

An Analytical Calculation Method for Displacement Criterion on Tunnel Surrounding Rock Mass Stability

Zhang

Chen

et al. 2022

Advances in Civil Engineering

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“…The interaction between subway tunnels and surface buildings was the main technical problem encountered in the construction of early urban subway projects. A series of studies have been carried out around this topic by many scholars [1,2]. As the urban population grows rapidly, the capacity of existing subways is no longer able to meet people's travel demands.…”

Section: Introductionmentioning

confidence: 99%

Numerical Parametric Study of Countermeasures to Alleviate the Tunnel Excavation Effects on an Existing Tunnel in a Shallow-Buried Environment near a Slope

et al. 2020

Applied Sciences

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This paper studies the influence law of existing tunnels on the construction of intersecting new tunnels in a shallow slope burial context through 3D numerical analysis. The emphasis is on exploring the effect of new tunnels constructed in 54 conditions, including three ratios of overburden to tunnel height (C/H), three ratios of slope distance to tunnel span (D/W), two backfilling conditions of the existing tunnel (“hty” and “htn” conditions), and three magnitudes of surface loads (10 kPa, 20 kPa, and 30 kPa), on the deformation of lateral slopes and the overlying road. As the results show, the rigidly separated area between the existing and newly built tunnels in parallel to the excavation direction was precisely the sensitive area affected by the existing tunnel backfilling condition. The road settlement simulations perpendicular to the excavation direction revealed that various C/H and D/W ratio combinations controlled the shape and size differences of the settlement trough curve. This was because the C/H ratio primarily controlled the effective span and height transition of the newly built tunnel, whereas the D/W ratio mainly controlled the intersection position of the tunnels. Next, model A-A (“hty” condition) was identified as the only feasible construction model among all models in accordance with the engineering safety control criteria. Lastly, comparison of monitoring data with simulations found a slight difference in the distribution pattern between the two. Nevertheless, the final maximum settlement fully satisfied the construction control requirements overall. Aside from proving the correctness of simulation results, the present study also sets an excellent referential example for similar projects.

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“…Regarding the mutual influence of tunnels during excavation, there are several reports on the influence of tunneling on the existing tunnels in the soil rock stratum using numerical or in situ monitoring methods, even by means of theoretical tools. A parametric study is performed based on numerical methods for a three-dimensional model to explore the complex interaction of the different parameters, which may affect the tunnel response on the open-pit mining sequence of existing tunnels [6]. In another example, the deformation of an existing tunnel is analyzed by 3D finite element methods (FEM), and the settlement of the overburden is obviously influenced by the structure of the existing tunnels through the plastic development of the soil layer [7,8].…”

Section: Introductionmentioning

confidence: 99%

Excavation Sequence and Surrounding Rock Mass Stability of Large‐Scale Underground Engineering with 8 Tunnels

Zhang

Chen

et al. 2020

Advances in Civil Engineering

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In some large-scale hydroelectric power projects, there are more than 3 tunnels that are too close to each other to eliminate the mutual influence during the excavation period, especially for large-scale tunnel groups. In this paper, aimed at analyzing the Bukun hydropower station consisting of 8 tunnels in Malaysia, the displacement, stress, and plastic zone of the surrounding rock mass are analyzed to study the effect of the excavation sequence on the stability of the surrounding rock mass for large-scale tunnel groups. On the one hand, the in situ monitoring of the surface displacement of the rock mass surrounding the tunnel using extensometers is performed to obtain the deformation characteristics on the excavation limit under the typical excavation sequence. On the other hand, a series of elastic-plastic 3D numerical experiments are carried out to explore the displacement characteristics, stability of the large-scale tunnel groups, and safety of the initial supporting system. The results show that the tendencies of the displacement increase corresponding to the tunnel face movement are similar for the three excavation sequences. The displacement under initial excavation sequence 2 (IES2) is the smallest among the three sequences; the area of the plastic zone under IES2 is the smallest among them; and the stresses in the shotcrete layer and axial forces in the rock bolt under the three excavation sequences are within the safety limitation. Initial excavation sequence 2 is an optimized excavation sequence, in which tunnels #1 and #5 are excavated first; after an advance of 3 times the diameter of the tunnel, tunnels #3 and #7 are excavated; tunnels #2 and #6 are excavated after an advance of 3 times diameters; and tunnels #4 and #8 are excavated after an advance of 3 times diameters.

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3D numerical parametric study of the influence of open-pit mining sequence on existing tunnels

Cited by 20 publications

References 26 publications

An Analytical Calculation Method for Displacement Criterion on Tunnel Surrounding Rock Mass Stability

An Analytical Calculation Method for Displacement Criterion on Tunnel Surrounding Rock Mass Stability

Numerical Parametric Study of Countermeasures to Alleviate the Tunnel Excavation Effects on an Existing Tunnel in a Shallow-Buried Environment near a Slope

Excavation Sequence and Surrounding Rock Mass Stability of Large‐Scale Underground Engineering with 8 Tunnels

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