Failure of rigid support and yielding support solution in large deformation tunnels: A case study

Tian, Hongming; Chen, Weizhong; Tan, Xianjun; Shu, Xiao-yun

doi:10.1016/j.engfailanal.2022.106598

Cited by 20 publications

(4 citation statements)

References 24 publications

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“…The test results show that the pressure of the secondary lining is reduced with the installation of the yielding layer. Tian el at [26] proposes a radial yielding support with a compressible layer as a solution for large deformation. Based on the proposed design method of yielding support, PE-foam with a density of 90 kg/m 3 -100 kg/m 3 is used as the filling material in the compressible layer.…”

Section: Introductionmentioning

confidence: 99%

Experimental study on yielding and relief pressure support technology of fluid-filled lining in a high-ground stress soft rock tunnel

Liu,

Wang,

Yang

et al. 2024

Scientia Iranica

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High-ground stress soft rock tunnels have experienced large deformations. Yielding and pressure relief fluid-filled lining support technology is an effective method for solving large soft rock tunnel deformation due to the deformation characteristics of high-ground stress soft rock tunnels. To give the surrounding rock a certain amount of deformation space, a layer of fluid filling is set up at the reserved deformation of the tunnel. By creating a force test model of the inflatable carcass and water-filled carcass, the straight section of the tunnel support structure is simulated. When supporting large deformation soft rock tunnels, inflatable and water-filled carcasses produce fluid homogenization load shedding and fluid drainage load shedding effects. Inflatable carcasses and water-filled carcasses without leakage reduce load by about 28% and 7%, respectively. The peak load reduction rate under liquid leakage can gradually reach 100 %. Inflatable carcasses can dissipate up to 90% of the work of external forces acting on the supporting structure. The load reduction rate of water-filled carcass is 1.2 times that of inflatable carcass. Fluid-filled materials can remove load from secondary lining support structures after yielding and pressure relief. Design and construction of high-ground stress soft rock tunnels can be influenced by research results.

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Section: Introductionmentioning

confidence: 99%

Experimental study on yielding and relief pressure support technology of fluid-filled lining in a high-ground stress soft rock tunnel

Liu,

Wang,

Yang

et al. 2024

Scientia Iranica

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“…Low-permeability unfavorable geological bodies such as mudstone, argillaceous interlayer, and mud-bearing fracture zone are commonly found in underground engineering in China [1,2]. Their occurrence state and pore structure characteristics are closely related to engineering construction, which, in many cases, has a significant impact on the safety and stability of engineering structures [3,4].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on the Gelling Properties of Nano-Silica Sol and Its Spontaneous Imbibition Grouting Mudstone

Zhao,

Xiang,

Zhang

et al. 2024

Processes

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The low-permeability argillaceous rock mass is an unfavorable geological body commonly found in the construction process of underground engineering conditions such as roadways and tunnels. Due to the compact structure and low permeability of the rock mass, grouting with conventional materials cannot effectively seal the micro-cracks of the rock mass. Based on the low efficiency of high-pressure grouting of nano-silica sol, this paper preliminarily explores the regularities and mechanism of grouting and pore sealing of low-permeability rock mass under the action of silica sol imbibition from the aspects of gelling properties of silica sol, core pore structure, imbibition law, and pore sealing characteristics. The results show the following: (1) The increase in particle size during the gel process reduced the injectability and wettability of the silica sol. The imbibition properties of silica sol were time-varying, and the deterioration inflection points of injectability and wettability appeared at 10 h and 9 h, respectively. (2) Catalyst, temperature, gel process, and rock mass permeability will affect the law of core imbibition, and the injectability and capillary force of the grouting material and rock mass will jointly affect the imbibition process of silica sol. (3) Silica sol imbibition changed the pore size distribution of the core, the pore volume above 50 nm decreased, and the pore volume below 50 nm increased. Silica sol has multiple effects such as filling, adsorption, and percolation in the imbibition process of the micro-pores of rock mass, and the adsorption and percolation of silica are related to the nano micro-pores.

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“…The mechanical behaviors of PUF are significantly affected by the foam density, [4][5][6][7][8] and the yield strength and deformation capacity of PUF can meet the demands of compressible layers if the appropriate density is selected. As the yielding support of subsea tunnels could be exposed to seawater, although PUF has been successfully used as a compressible layer in some squeezing tunnels running through mountains, 2,9,10 the salt concentration of seawater is significantly higher than that of groundwater, which induces some functional groups in the macromolecular structure of PUF may become unstable. Therefore, the determination of whether PUF losses its mechanical properties after longterm immersion in seawater is of great significance for the yielding support of subsea tunnels.…”

Section: Introductionmentioning

confidence: 99%

“…Yielding support in squeezing tunnels: (a) tangential yielding support with compressible element and (b) radial yielding support with compressible layer 2 …”

Section: Introductionmentioning

confidence: 99%

Experimental study on the availability of polyurethane foam used as compressible layers in subsea tunnels

Zhang,

Tian,

Chen

et al. 2023

J of Applied Polymer Sci

Self Cite

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The yielding support comprising a compressive layer is considered as a solution to the time‐dependent damage of the lining in squeezing tunnels. The feasibility of the use of polyurethane foam (PUF) as the compressible layers in subsea tunnels was investigated in this study. Confined compression tests were conducted to investigate the compression performance degradation of PUF immersed in artificial seawater for 400 days. The yield strength and elastic modulus of PUF decreased within 180 days but then increased to over 80% of their initial values within the subsequent following 220 days, the degradation rate and strengthening rate of these parameters are of the same order of magnitude. The degradation rate of the yield strength and elastic modulus can be significantly inhibited by ions in artificial seawater, thus causing samples immersed in low‐salt‐concentration solutions to exhibit worse compression performance than those of samples immersed in a high‐salt‐concentration solution. The stress at the end of the yielding plateau and yielding plateau strain range were slightly affected by hydrolysis aging. The shape of the yielding plateau stage of the aged samples changed from a horizontal line to an inclined line owing to the variation in the yield strength. Even after immersion for 400 days, all the aged samples still exhibited compression failure and neither crumbled into pieces nor fractured into parts. The strengthening effect, unchanged failure mode, and almost constant yielding plateau strain range guarantee the safe utilization of PUF in marine environments.

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Failure of rigid support and yielding support solution in large deformation tunnels: A case study

Cited by 20 publications

References 24 publications

Experimental study on yielding and relief pressure support technology of fluid-filled lining in a high-ground stress soft rock tunnel

Experimental study on yielding and relief pressure support technology of fluid-filled lining in a high-ground stress soft rock tunnel

Experimental Study on the Gelling Properties of Nano-Silica Sol and Its Spontaneous Imbibition Grouting Mudstone

Experimental study on the availability of polyurethane foam used as compressible layers in subsea tunnels

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