Failure analysis and control measures for tunnel faces in water-rich sandy dolomite formations

Jiang, Yifan; Zhou, Ping; Zhou, Feicong; Lin, Jeffrey S.; Li, Jinyi; Lin, Meng-Hsuan; Yongli, Qi; Wang, Zhijie

doi:10.1016/j.engfailanal.2022.106350

Cited by 32 publications

(7 citation statements)

References 21 publications

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“…In particular, excavations in multi-aquifer-aquitard strata, abundant in groundwater, present considerable risks [4]. Groundwater control is thus imperative to prevent water inrush accidents and ensure the safety of underground construction [5][6][7][8][9][10][11][12][13][14]. However, inappropriate dewatering can lead to undesirable consequences such as soil deformation, differential settlement, and sand flow or piping [15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Field Experiments on 3D Groundwater Flow Patterns in the Deep Excavation of Gravel-Confined Aquifers in Ancient Riverbed Areas

Xu,

Shi,

Wang

et al. 2023

Applied Sciences

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In ancient riverbed areas, the hydro-geological conditions are extremely complex because of the cutting of ancient river channels during the sedimentary process. How to lower groundwater level in water-riched gravel-confined aquifer during deep excavation is vital for underground engineering. Groundwater flow patterns had to be understood during foundation pit dewatering. This paper presents a field case study conducted at the deep foundation pit of the Qianjiang Century City station on Hangzhou Metro Line 6, which is notable for its 52 m deep unclosed waterproof curtain. A total of 34 pumping wells were installed within the pit. During the tests, one well was subjected to a pumping well, while the others served as observation wells. The research included two sets of multi-depth pumping tests, which differed in terms of their filter lengths, aimed at investigating the flow pattern around pump wells and the roots of diaphragm walls. The study found that the use of longer filters, higher pump rates, and filters placed nearer to aquifer roofs enhances dewatering efficiency and minimizes impact on the surrounding geological environment. This paper introduces a novel concept known as the diaphragm wall–pumping well effect, which regulates the water head outside the pit and the subsidence, thereby optimizing the drawdown of the deep foundation pit with an unclosed waterproof curtain. The findings were applied in the foundation pit dewatering of Qianjiang Century City station, and the drawdown in and outside the pit was effectively controlled.

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Section: Introductionmentioning

confidence: 99%

Field Experiments on 3D Groundwater Flow Patterns in the Deep Excavation of Gravel-Confined Aquifers in Ancient Riverbed Areas

Xu,

Shi,

Wang

et al. 2023

Applied Sciences

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“…Liang et al (2019) investigated the effect of intermediate principal stress and lateral pressure coefficient on the failure behavior of deep tunnels. Jiang et al (2022) analyzed the deformation and pressure arch characteristics of roadway face in water-rich sandy dolomite stratum by fluid-solid coupling model and proposed the limit equilibrium theory considering seepage effects and pressure arch characteristics. Yan et al (2021) studied the mechanism of the collapse of funnel-shaped stratum through numerical simulation and found that the essence of the collapse is the process of converting potential energy into kinetic energy.…”

Section: Introductionmentioning

confidence: 99%

Sandy aquifer collapse mechanism and accident treatment of the Qingdao metro tunnel

Zhang,

Wang,

Zhang

et al. 2023

Front. Earth Sci.

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The tunnel collapse occurred during the construction of the Qingdao Metro Line Ⅰ, resulting in a pit measuring approximately 10 m in diameter and 7 m in depth on the ground surface. The collapse inflicted substantial economic losses, casualties, and subsequent disruptions to ongoing construction activities. To clarify the causes of this collapse and investigate the underlying factors, a comprehensive approach combining field surveys and numerical simulations was undertaken. The results show that the collapse was primarily attributed to inadequate support when facing the challenging geological conditions, poor surrounding rocks (Grade VI) and a high volume of groundwater. The combination of abundant water and sand seeped into the tunnel, culminating in a catastrophic ground collapse. Notably, the arch roof experienced extensive deformation and damage due to the significant seepage pressure, which was exacerbated by the absence of timely support. Then, ground grouting was promptly conducted to repair the affected area and reinforce the tunnel structure. Subsequent monitoring of surface deformations following the resumption of tunneling operations indicated the effectiveness of the disaster treatment approach. These achievements constitute a reliable theoretical foundation for similar projects, particularly in terms of environmental protection and ensuring safe construction practices.

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“…Wang et al [31], based on the sanding phenomenon of dolomite developed from Triassic and Cambrian in five tunnels of Guizhouto, analyzed both the sanding patterns and characteristics of dolomite, proposing the reinforcement methods and solutions under the specific condition of argillaceous dolomite sanding. Based on the double-track centralized tunnel project of the Chengdu-Kunming railway, Jiang et al [35] revealed that the necessary conditions for dolomite to become sand gushings were being sandy in water environment; Zhou et al [36] investigated the Emeishan-Miyi section tunnel of the Chengdu Kunming railway extension project crossing the sandy dolomite stratum from September 2017 to November 2020, with four water and sand gushing accidents at different levels occurring at different positions of the tunnel surface. Moreover, the reconstructed Jiermu (Jixin) tunnel [37] of the Chengdu-Kunming Railway in Sichuan Province also passed through the sanding dolomite stratum of Dengying Formation of Sinian System, with "water and sand gushing" also occurring frequently in the water-rich section.…”

Section: Introductionmentioning

confidence: 99%

Study on Construction and Reinforcement Technology of Dolomite Sanding Tunnel

Wang

et al. 2022

Sustainability

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The No. 2 conduit of the Xiaopu Tunnel in the Yuxi section of central Yunnan’s water diversion project is taken as the research object, starting from the geological conditions along with the characteristics, formation mechanism and evolutionary model of dolomite sanding. This paper discusses the engineering problems of the project’s tunnels with dolomite sanding in the water-rich section, and its corresponding engineering reinforcement plan. It was found that in the tunnel section with normal level of dolomite sanding, there was no water seepage, where measures such as advanced small conduit, mechanical excavation, short grubbing and strong support could all be adopted for safe passage. Even in the water seepage section of the weak dolomite sanding tunnel, the surrounding rock was found in close interlock with strong self-stability. The excavation and support were implemented according to the category of normal surrounding rock. In the water-rich sections with strong and intense dolomite sanding, gushing of water and sand were quite frequent, with developed fissures, broken rock masses and rich waters. During the engineering operation, phosphoric acid and sodium silicate slurry in addition to urea formaldehyde resin and oxalic acid slurry plus Malisan and liquid catalyst slurry were first prepared for water plugging. Then, pure water slurry was used for surrounding rock reinforcement, which exerted an excellent effect. This method can provide reference for reinforcing tunnels of sandy dolomite in other areas of projects.

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Failure analysis and control measures for tunnel faces in water-rich sandy dolomite formations

Cited by 32 publications

References 21 publications

Field Experiments on 3D Groundwater Flow Patterns in the Deep Excavation of Gravel-Confined Aquifers in Ancient Riverbed Areas

Field Experiments on 3D Groundwater Flow Patterns in the Deep Excavation of Gravel-Confined Aquifers in Ancient Riverbed Areas

Sandy aquifer collapse mechanism and accident treatment of the Qingdao metro tunnel

Study on Construction and Reinforcement Technology of Dolomite Sanding Tunnel

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