scholarly journals Study on Deep and Large Foundation Pit of a National First-Class Key Tomb Protection Project

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Jiagang Zhang ◽  
Zhimin Chen ◽  
Mingzhu Hu ◽  
Zhaoguo Wu
Keyword(s):  
Numerical Analysis ◽  
Large Range ◽  
Retaining Wall ◽  
Bending Moment ◽  
Foundation Pit ◽  
Reinforcement Scheme ◽  
Bored Pile ◽  
Maximum Value ◽  
The Stability ◽  
Support Engineering

For the support engineering of the deep and large foundation pit (DLFP) due to tomb protection, there are still no clear standards. The construction of DLFP will introduce large-range transverse and longitudinal disturbance on the stratum; therefore, it should be reinforced. In this paper, the reinforcement of the deep and large foundation pit of a national first-class key tomb protection project is studied. By comparing the existing supporting scheme and the stress conditions of the reinforced tomb, the combination reinforcement scheme by bored pile and pile slab retaining wall is found to be safe and feasible. Furthermore, according to the simulated bending moment, displacement, and axial force of the tomb by numerical analysis, an economic and reasonable mixed anchor support scheme is selected. In order to ensure the stability of the tomb during the supporting process of the foundation pit, a maximum value of 10 mm for the overall settlement of the tomb can be treated as the control benchmark based on the support and anchorage schemes in each specification and the in-site measured settlement values of the tomb. The determined support, anchorage schemes, and the control benchmark can provide certain technique guidance and research significance for the protection of similar ancient buildings in the future.

scholarly journals Numerical Analysis on the Performance of the Underwater Excavation

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Bo Li ◽  
Cangqin Jia ◽  
Guihe Wang ◽  
Jun Ren ◽  
Gaofeng Lu ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Retaining Wall ◽  
Lateral Wall ◽  
Surface Settlement ◽  
Design Parameters ◽  
Analysis Model ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Wall Deflection ◽  
Total Settlement

Based on the Yongdingmen Station of Beijing Metro, the underwater excavation method for deep foundation pit was introduced. This study constructed a numerical analysis model to analyze the performance of surface settlement and lateral wall deflection in the process of underwater excavation. Results showed that this method was better to control the surface settlement and lateral wall deflection compared with other dewatering excavations. In detail, most of the surface settlement was caused during the dry excavation stage and dewatering excavation stage while the deflection caused by underwater excavation only accounted for about 10% of the total settlement. Besides, the maximum settlement occurred 0.25∼0.5 H e behind the retaining wall and the value was 0.04% H e . Similar to the result of the surface settlement, most of the lateral wall deflection had been completed before the underwater excavation, which only caused about 7% of the total deflection. The maximum wall deflection and its location were approximately 0.06% H e and 0.5 H e , respectively. Moreover, a series of 3D numerical analyses were studied on the design parameters of the underwater excavation method. This study can be used as a reference for general performance and structural design of foundation pits with underwater excavation.

Numerical Analysis on the Influence of Joints Inclination on the Characteristics of Deformation and Stability of Tunnel

2013 ◽  
Vol 790 ◽  
pp. 299-305
Author(s):  
Xiao Song Tang ◽  
Yong Fu Wang ◽  
Ying Ren Zheng
Keyword(s):  
Stability Analysis ◽  
Numerical Analysis ◽  
Calculation Method ◽  
Research Result ◽  
Bending Moment ◽  
Surrounding Rock ◽  
Interface Element ◽  
Tunnel Stability ◽  
Stability Of Surrounding Rock ◽  
The Stability

The paper adopts the interface element to simulate the joints so as to systematically and quantitatively study the deformation around tunnel, the mechanic state of lining and the stability under different inclining angles of joints. The result shows that the deformation around tunnel deteriorates mainly along the joint during the inner convergence effects of surrounding rock. When the inclining angle α=45°, the deformation around the tunnel is most serious, followed by that when α=90°, α=60°, α=30° and α=0°. At the same time, the influence of inclining angle on the distribution of the axial force of lining is comparatively small. But the distribution of bending moment and shear change obviously where the joints penetrate the tunnel. The tunnel stability of surrounding rock is the poorest when α=90° and the tunnel is most stable when α=0°. The stability of surrounding rock changes little when α is between 30° and 60°. The research result provides an effective calculation method for the forecast of deformation, the design of structure and the stability analysis of jointed tunnel. It is also helpful for the monitoring of construction and calculation of jointed tunnel in the future.

scholarly journals Review on “Assessment of the effect of lateral dynamic forces on rcc cantilever l-shaped and t-shaped retaining wall with height variations”

2021 ◽  
Vol 1197 (1) ◽  
pp. 012030
Author(s):  
Jayesh Harode ◽  
Kuldeep Dabhekar ◽  
P.Y. Pawade ◽  
Isha Khedikar
Keyword(s):  
Retaining Wall ◽  
Earth Pressure ◽  
Bending Moment ◽  
Retaining Walls ◽  
Wall Material ◽  
Dynamic Forces ◽  
Present Design ◽  
Cantilever Retaining Walls ◽  
The Stability ◽  
Manual Calculation

Abstract It is now becoming very essential to analyse the behaviour of retaining structures due to their wide infrastructural applications. The important factors which are affecting the stability of the retaining wall are the distribution of earth pressure on the wall, material of backfill & its reaction against earth pressure. There are several types of retaining walls, out of them the cantilever retaining wall is adopted for present design and study. In this paper, the study of literature based on the design of the cantilever retaining walls under seismic or dynamic conditions is studied. From the studied literature, many authors performed their calculations in Excel sheets by a manual method. Then the Results obtained from the manual calculation are then validated in STAAD pro. Several authors show the calculated quantity of steel and concrete required for various heights of walls. It is also concluded from the study that the design of cantilever retaining wall is suitable, safe, and economical up to a height of 6m, after that banding moment at toe increases. Some authors have also shown the calculated factor of safety for different height conditions. From the study of mentioned literature, we can recommended to also show the graph of bending moment with height variation. Both the designs are done for various heights ranging from 3 m to 6 m.

scholarly journals Dynamic Numerical Analysis of Displacement Restraining Effect of Inclined Earth-Retaining Structure during Embankment Construction

2019 ◽  
Vol 9 (11) ◽  
pp. 2213 ◽  
Author(s):  
Su-Won Son ◽  
Minsu Seo ◽  
Jong-Chul Im ◽  
Jae-Won Yoo
Keyword(s):  
Numerical Analysis ◽  
Maximum Stress ◽  
Lateral Displacement ◽  
Retaining Wall ◽  
Field Tests ◽  
Front Wall ◽  
Construction Process ◽  
Construction Methods ◽  
Excavation Process ◽  
The Stability

Retaining walls are generally used for temporary installations during the excavation process of a construction project. They are also utilized to construct embankments in order to extend a railway facility. In this case, a retaining wall is installed during the construction process and contributes to the resistance of large amounts of stress, including the railway load. However, it is generally difficult to retain walls to maintain their stability. Therefore, alternative construction methods, such as the use of an inclined earth-retaining wall, have been utilized to suppress the lateral displacement. The stability is verified in advance through field tests; however, the maximum stress acting on the railway is thought to be the concentrated railway load. In this study, a two-dimensional numerical analysis was conducted by changing the railway load to a dynamic load. The analysis was applied according to the number of H-piles of the same length (10 m) when only the front wall was installed and when a back support was also applied. It was determined that the lateral displacement of the latter case is smaller than that of the former, whereas the resistance to dynamic loading of the former case is greater.

Stability on Supporting Structure of Deep Foundation Pit with Infiltration

2012 ◽  
Vol 170-173 ◽  
pp. 223-226 ◽  
Author(s):  
Xue Song Gao ◽  
Jian Jun Dong ◽  
Xu Zhao ◽  
Peng Yang Yin ◽  
Shao Hua Lv
Keyword(s):  
Bending Moment ◽  
Rainfall Infiltration ◽  
Deep Excavation ◽  
Initial State ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Building Foundation ◽  
Internal Forces ◽  
The Stability

The FLAC3D was used to the fluid-solid coupling numerical simulation of considering the initial state of unsaturated to soil for the deep foundation pit engineering under different rainfall infiltration conditions. By comparing the bending moment, the shearing stress and internal forces of support under the infiltration conditions between non-rainfall and rainfall, the paper focus on the stability of deep foundation pit. Research on the stability of deep excavation under rainfall conditions was a useful attempt. From the detail study of the stability of a foundation pit of Qinhuangdao under rainfall infiltration conditions, the paper have drawn some useful conclusion on the design of building foundation pit, which can be the basis of excavation design and construction under rainfall conditions.

scholarly journals Experimental and Numerical Investigation on the Effects of Foundation Pit Excavation on Adjacent Tunnels in Soft Soil

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Zi-Tian Yu ◽  
Heng-Yu Wang ◽  
Wenjun Wang ◽  
Dao-Sheng Ling ◽  
Xue-Dong Zhang ◽  
...  
Keyword(s):  
Retaining Wall ◽  
Soft Soil ◽  
Shear Bands ◽  
Earth Pressure ◽  
Bending Moment ◽  
Surface Settlement ◽  
Diaphragm Wall ◽  
Foundation Pit ◽  
Obvious Effect ◽  
Diaphragm Walls

Excavations near an existing tunnel are often encountered in underground construction. The influence of the excavation on the adjacent tunnels is not yet fully understood. This study presented a centrifugal model test about excavation next to existing tunnels in soft soil foundation. The bending moment of diaphragm wall, surface settlement, tunnel deformation, and earth pressure around the tunnel were mainly studied. The influence of tunnel location is further studied by numerical simulation. During the stabilization stage of foundation pit, the diaphragm walls present convex deformation towards foundation pit, and the surface settlement outside the diaphragm wall appears to be the concave groove type. During the overexcavation stage, the diaphragm walls are almost damaged, and the shear bands are nearly tangent to the tunnels. The displacement of the tunnels and the surface settlement rapidly increase. The deformation of the diaphragm wall and the surface settlement are limited by the existing tunnel. The numerical results indicate that the change of tunnel location has little effect on the retaining wall but an obvious effect on the tunnel itself.

The Safety Assessment of Bored Pile Retaining Wall Based on Back Analysis for Bending Moment

2013 ◽  
Vol 353-356 ◽  
pp. 1015-1023
Author(s):  
Tao Liu ◽  
Yun Bin Chen
Keyword(s):  
Safety Assessment ◽  
Retaining Wall ◽  
Engineering Application ◽  
Back Analysis ◽  
Cost Savings ◽  
Bending Moment ◽  
Internal Force ◽  
Deep Foundation ◽  
Bored Pile ◽  
Foundation Pile

Dynamic safety assessment of internal force of retaining wall is of great significance to ensure the safety construction of deep foundation pile, and the key is to get the actual bending moment. The curvature is acquired by curve fitting of retaining wall reformation with the least squared method, and the actual bending moment can be obtained by multiplying the curvature and retaining wall bending stiffness. This method overcomes the difficult that the actual bending moment cannot be directly measured, at the same time, the cost savings would be of great advantage. As the monitoring item of foundation pile which must be implemented, retaining wall deformation has sufficient data, which provide a solid foundation for the engineering application of back analysis of bending moment. This studied the safety assessment of bored pile retaining wall based on back analysis for bending moment and obtained some beneficial conclusions.

Application of Mc Composite Retaining Structure in the Silt Soil Foundation

2013 ◽  
Vol 353-356 ◽  
pp. 341-346
Author(s):  
Ying Cheng ◽  
Ai Zhao Zhou
Keyword(s):  
Retaining Wall ◽  
Ground Surface ◽  
Bending Moment ◽  
Horizontal Displacement ◽  
Foundation Pit ◽  
Wall Width ◽  
Obvious Effect ◽  
Retaining Structure ◽  
Supporting Structure ◽  
Soil Foundation

This pape combined with the engineering example of a supporting muddy soil foundation pit,used the finite element numerical analysis method, discussed on mechanical deformation characteristics of the cement-soil pile and concrete pile composite retaining structure (MC pile for short ) , Including the effect of section parameters of MC pile on the horizontal displacement of supporting structure, settlement of ground surface and bottom heave. The results show that, MC pile composite retaining structure are beneficial to control the deformation of foundation pit, and increase the stability of foundation pit; M pile retaining wall width to reduce the deformation of the retaining structure has obvious effect, which increase the width of wall can decrease the bending moment ,inclination deformation of supporting structure and lowe bottom heave and surface settlement. Moreover, in the same wall width, there is no C pile to control the deformation of the retaining structure and deformation of the foundation also has a great role.

Design of Structure and its Enclosure for Subaqueous Tunnel to Cross River in Urban Highway Line

2014 ◽  
Vol 488-489 ◽  
pp. 390-393 ◽  
Author(s):  
Xiao Jun Zhou ◽  
Guo Rui
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structure ◽  
Reinforced Concrete Structure ◽  
Foundation Pit ◽  
River Bank ◽  
Cross River ◽  
Soil Mixing ◽  
Bored Pile ◽  
River Bed ◽  
The Stability

This paper summarizes the design of reinforced concrete structure and its enclosure for a subaqueous tunnel used to cross a river in urban highway line. The tunnel mainly consists of open-cut section on river bank and cut-cover section under river bed. Their structure and enclosure are both illustrated in the paper according to site geology and general layout of urban highway line. The use of rotary bored pile and soil mixing wall to preserve the stability of open-cut foundation pit are summarized in the paper.

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