Analysis on Deformation and Stress Characteristics of a Multibraced Pit‐in‐Pit Excavation in a Subway Transfer Station

Shi, X.; Rong, Chuanxin; Cheng, Hua; Cui, Linzhao; Wang, Bin; Sun, Shicheng

doi:10.1155/2020/8844461

Cited by 7 publications

(7 citation statements)

References 18 publications

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“…The uplift at the bottom of the foundation pit of the auxiliary tunnel was also controlled within 3 cm. This is consistent with the results of previous studies [28][29][30].…”

Section: Resultssupporting

confidence: 94%

Design, construction and analysis for super-wide, deep and large foundation pit

Shi

Tian

Zheng³

et al. 2021

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Both developing and developed countries are facing a series of difficulties and challenges in the process of urbanization. In recent years, in order to alleviate the problem of urban congestion, underground space has developed rapidly, and the excavation of foundation pit is the most important step in the development of underground space. This paper takes the foundation pit of the tunnel under construction in Suzhou as a research object. The design width of the foundation pit reaches 61.5 m and the depth reaches 18 m, so it belongs to the super wide and deep foundation pit. Numerical analysis is performed by finite element software to calculate the deformation of the foundation pit. The research shows that the main problem to be solved is the deformation of the foundation pit, and the deformation of side wall of foundation pit tunnel is the most obvious. The maximum deformation of the side wall of the main tunnel and the auxiliary tunnel reached the maximum at 15 m. The maximum deformation of the main tunnel is about 1.3 cm, and that of the auxiliary tunnel is about 0.9 cm. Through targeted design and construction, the mechanical performance of the foundation pit retaining structure is optimized, and the stability of the foundation pit is strengthened. The reasonable retaining structure can ensure the good construction quality. The design and construction of the project can provide reference for related engineering construction.

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“…The uplift at the bottom of the foundation pit of the auxiliary tunnel was also controlled within 3 cm. This is consistent with the results of previous studies [28][29][30].…”

Section: Resultssupporting

confidence: 94%

Design, construction and analysis for super-wide, deep and large foundation pit

Shi

Tian

Zheng³

et al. 2021

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“…FEM Model. A three-dimensional numerical model was established with GTS/NX software, which has often been used in the excavation simulation [29,30]. e model of the shielding tunnels undercrossing the pipeline was established to simulate the whole process of the construction, and the sizes of the tunnels and the pipeline in the model were consistent with the actual sizes.…”

Section: Three-dimensional Numerical Modelmentioning

confidence: 99%

“…e basic mechanical parameters of the soil were provided in the geological report. e parameters we needed mainly referred to the study of Shi et al [30]. In [30], the data was obtained from experiments and verified with the field measured data.…”

Section: Materials Model and Parametersmentioning

confidence: 99%

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The Ground Settlement and the Existing Pipeline Response Induced by the Nonsynchronous Construction of a Twin‐Tunnel

Sun

Rong

Wang

et al. 2021

Advances in Civil Engineering

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Shielding tunnel construction always has negative impacts on the surrounding buildings. Because of repeated disturbances caused by the construction, more attention should be paid to the impacts of the nonsynchronous construction of a twin-tunnel. In this research, a three-dimensional model was established to simulate the construction process of a twin-tunnel in a section of the Hefei No. 4 metro line, and the calculation results were validated with the measured settlement data. Based on the model, the ground settlement and the existing pipeline responses were studied in detail. The results showed that, after the first tunnel (FT) construction, the settlement curves conformed to a Gaussian distribution. Additionally, after the second tunnel (ST) construction, the final settlement curves were no longer completely symmetrical. The influences of the twin-tunnel space and the pipeline-soil relative stiffness on the settlements were further studied. The results showed that the final settlement curves of the ground surface and the pipeline were mainly W-shaped, U-shaped, and V-shaped. As the twin-tunnel space increased and the pipeline-soil relative stiffness decreased, the settlement curve gradually changed from V-shaped to W-shaped. C was defined as the ratio of two maximum settlements in the W-shaped settlement curve. As the space increased, C started to decrease from 1 and then increased to 1.

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“…e design depth of the foundation pit of Jianguo Road Station of Hangzhou Metro Line 5 is 25.6 m. e reinforced concrete brace has tensile stress, and the maximum tensile force is about 1500 kN [9]. e design depth of the foundation pit of an air shaft of a subway in Shanghai is 25.07 m, and the reinforced concrete brace has tension during construction [10,11].…”

Section: Introductionmentioning

confidence: 99%

Field Experimental Study on Mechanical Properties of Frame Support Structure Composed of Subway Foundation Pit Retaining Pile and Steel Strut Rigid Joint

Huang

Zhang

Chen

et al. 2022

Advances in Civil Engineering

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In order to study the advantages of frame support structure composed of rigid joint between steel strut and retaining pile in restraining the lateral displacement of retaining structure and maintaining the stability of foundation pit, foundation pit failure test was carried out. Compared with the traditional support structure, which can only bear pressure composed of steel strut and retaining pile lap joint, the variation characteristics of pile lateral displacement and support axial force of frame support structure under the influencing factors, such as weak stratum, pit side loading, groundwater level rise, and support drop, are studied. The test results show that, compared with the traditional steel strut, the pile-strut frame support structure can not only bear the compressive stress, but also the tensile stress caused by the lateral displacement of the top of the retaining pile outside the foundation pit. The overall stability is better, and the axial force distribution of each layer of support is more uniform so as to reduce the overall lateral displacement of the retaining pile. In the process of foundation pit collapse, the frame support structure will not have the problem of strut falling, which can maintain part of the support capacity, prolong the collapse time of retaining piles, strive for more escape time for front-line construction workers, and reduce the number of casualties.

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Analysis on Deformation and Stress Characteristics of a Multibraced Pit‐in‐Pit Excavation in a Subway Transfer Station

Cited by 7 publications

References 18 publications

Design, construction and analysis for super-wide, deep and large foundation pit

Design, construction and analysis for super-wide, deep and large foundation pit

The Ground Settlement and the Existing Pipeline Response Induced by the Nonsynchronous Construction of a Twin‐Tunnel

Field Experimental Study on Mechanical Properties of Frame Support Structure Composed of Subway Foundation Pit Retaining Pile and Steel Strut Rigid Joint

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