scholarly journals An Experimental Study on the Ecological Support Model of Dentate Row Piles

2020 ◽  
Vol 2020 ◽  
pp. 1-12 ◽  
Author(s):  
Yousheng Deng ◽  
Zhihe Cheng ◽  
Mengzhen Cai ◽  
Yani Sun ◽  
Chengpu Peng
Keyword(s):  
Building Materials ◽  
Soft Soil ◽  
Earth Pressure ◽  
Shallow Foundation ◽  
Laboratory Model ◽  
Foundation Pit ◽  
Maximum Displacement ◽  
Single Row ◽  
The Earth ◽  
Soil Foundation

Bamboo is highly renewable and biodegradable with good short-term strength, which meets the requirement for temporal support structures in shallow foundation pits. Based on this, we conducted a laboratory model test on the dentate bamboo micropile support structure combined with environmentally friendly building materials and new type of piles, to explore the stress characteristics, stress change regularity, and the support effect of the system in soft soil foundation pits. The results show that the earth pressure on the pile sides above the excavation surface gradually decreases with an increase in the excavation depth. The bending deformation of the bamboo pile was also significant. The results also show that the earth pressure and the pile strain below the excavation surface change slightly during the excavation process. When the short sides of the foundation pit were loaded, the highest strain was recorded in the piles 4 and 11. A maximum strain of 358.93 με was recorded, and the maximum displacement of the pile in the top part was obtained to be only 2.14 mm. The most subsidence of dentate pile obtained is only 1.88 mm, whereas that of the single-row pile is 2.35 mm. Compared to the traditional single-row pile, the dentate piles can effectively reduce the horizontal deformation as well as the surface subsidence effectively. They can also support more external lateral load, and hence maintain the foundation stability and give better support. The results provide a theoretical basis for ecological bamboo support technology and have great value to be promoted.

Numerical Simulation of Construction of Super-Large Deep Soft Soil Foundation Pits and Analysis of its Spatial and Temporal Effects

2015 ◽  
Vol 724 ◽  
pp. 79-83
Author(s):  
Xiao Qin Wang ◽  
Ting Ting Sun
Keyword(s):  
Constitutive Relations ◽  
Soft Soil ◽  
Earth Pressure ◽  
Deep Foundation ◽  
Support Structure ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Soil Foundation ◽  
Soft Soil Foundation ◽  
Deep Soft Soil

The constitutive relations of soil in the super-large deep foundation pit project and the law of interaction between soil and the support structure were studied. The excavation of the foundation pit was simulated. The coupling of soil and the support structure and the change in earth pressure with the progress of excavation were analyzed, and the scope of influence of foundationsubsidence was obtained.

Analyses of Earth Pressure on Gridding Concrete Retaining Wall in the Excavation of Deep Foundation Pit in Soft Soil Area

2011 ◽  
Vol 52-54 ◽  
pp. 2181-2186
Author(s):  
Guang Zhu Zhou ◽  
Xu Wei ◽  
Chen Yu
Keyword(s):  
Retaining Wall ◽  
Soft Soil ◽  
Earth Pressure ◽  
Front Wall ◽  
Three Dimension ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Finite Element Software ◽  
The Earth ◽  
Practical Engineering

This paper is mainly to study earth pressure on Gcrw used as a new kind of supporting structures in the excavation of deep foundation pits in soft soil region. On the basis of the simulation of step by step excavation by using big finite element software Abaqus/CAE and considering three-dimension elastoplastic stress state, the characteristics of different earth pressure are systematically discussed upon practical engineering. By comparing simulation results with calculated results based on calculation formula of Rankine Theory, it can be seen that the earth pressure in active zone is different from theoretic active earth pressure and earth pressure at rest while walls and soil in the gridding are regarded as a whole, which is greater than the former and somewhere similar to the latter, the earth pressure in passive zone is bigger than theoretic value of passive earth pressure, it is the tensive force from partition wall that prevent the front wall from overturning. These conclusions will be helpful for design and construction of new retaining wall.

scholarly journals Determination of Embedded Depth of Soldier Piles in Pile-Anchor Supporting System in Granite Residual Soil Area

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Yiao Liu ◽  
Changming Wang ◽  
Xiaoyang Liu ◽  
Ruiyuan Gao ◽  
Bailong Li ◽  
...  
Keyword(s):  
Earth Pressure ◽  
Residual Soil ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Maximum Displacement ◽  
Deep Foundation Pit ◽  
The Earth ◽  
Granite Residual Soil ◽  
Surrounding Soil ◽  
Soil Area

Reasonable depth of pile embedment is one of the key factors for the success of deep foundation pit projects. This paper has taken a deep foundation pit project in a granite residual soil area in Shenzhen as an example and used physical model tests to study the deformation law of the piles and the surrounding soil during the excavation of the deep foundation pit, revealing the variation law of earth pressure in time and space in the pit and then verified it by numerical simulation. The influence of the embedded depth of the pile on the deformation and earth pressure of the deep foundation pit is then explicitly discussed. The study shows that the embedded depth has a significant effect on the deformation and earth pressure distribution of the foundation pit. The earth pressure in front of the pile tends to approach the passive earth pressure as the embedment depth decreases, while the earth pressure behind the pile is in between the Rankine active earth pressure and the static soil pressure; the settlement value and settlement range of the surrounding soil are doubled. The pile displacement increases as the maximum displacement point rises. The maximum displacement of the pile body was used as the basis for determining the instability of the foundation pit. The optimum embedded depth is obtained when the depth of embedment of the pile is 0.22 H (H is the excavation depth of the foundation pit).

scholarly journals Study on Supporting Structure Performance of Deep Soft Soil Foundation Pit near Sea under Waves, Tides, Vibration, and Unbalanced Loads

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Junsheng Chen ◽  
Chen Lin ◽  
Shuzhuo Liu ◽  
Haihong Mo
Keyword(s):  
Mechanical Performance ◽  
Soft Soil ◽  
Offshore Structure ◽  
Foundation Pit ◽  
Supporting Structure ◽  
Vibration Loads ◽  
Soil Foundation ◽  
Soft Soil Foundation ◽  
Unbalanced Loads ◽  
Offshore Foundation

In addition to the vibration loads caused by offshore structure construction, the offshore foundation pit can also be affected by additional hydraulic loads such as waves, tides, and typhoons, hindering our understanding of the mechanical performance of the foundation pit supporting structure. In order to illuminate this mechanical performance under waves, tides, hammering, and unbalanced loads, this paper analyzed the supporting structure with theoretical and numerical simulations. The results were verified with field monitoring data. Moreover, the influences of loads, including construction vibration loads and unbalanced loads, on structure and soil were discussed. By applying these results to the engineering design, this research could provide a reference for studying mechanical properties of relevant supporting structures and the construction of offshore foundation pits.

Study on Vibro-Replacement Stone Pile Test for Soft Soil Foundation

2014 ◽  
Vol 543-547 ◽  
pp. 3982-3985
Author(s):  
Tie Liang Li ◽  
Jing Meng ◽  
Qiang Zhang ◽  
Gan Zhang ◽  
Lei Fei Deng ◽  
...  
Keyword(s):  
Soft Soil ◽  
Standard Penetration Test ◽  
Reinforcement Effect ◽  
Feeding Mode ◽  
The Earth ◽  
Feeding Type ◽  
Before And After ◽  
Undrained Strength ◽  
Soil Foundation ◽  
Soft Soil Foundation

This paper studies the applicability of vibro-replacement stone pile in combination of a port project in Dalian as well as heavy dynamic sounding and standard penetration test, studies the reinforcement effect of pile distance and feeding type on vibro-replacement stone and analyzes reinforcement effects of the side pile and the earth among piles. The results show: smaller pile distance will bring better pile compactness; for the vibro-replacement stone pile constructed in soft earth with undrained strength less than 20kPa with the conventional method, it is not easy to form compact pile; the reinforcement effect works only within 0.6m on the top; vibro-replacement stone pile with bottom feeding mode can form compact piles, but the pile has the interlayer which is not compact enough partially; the strength of the earth among piles fails to improve obviously before and after the stone pile is formed.

Stability Analysis of Soft Soil Foundation Excavation of Underground Station in Coastal Area of Tianjin

2014 ◽  
Vol 501-504 ◽  
pp. 1761-1765
Author(s):  
Yu Ting Zhang ◽  
Dian Jun Zuo ◽  
Wen Bin Pei ◽  
Xiao Qiang Liu
Keyword(s):  
Water Level ◽  
Coastal Area ◽  
Flow Instability ◽  
Soft Soil ◽  
Simulation Method ◽  
Underground Water ◽  
Foundation Pit ◽  
Ground Crack ◽  
Soil Foundation ◽  
Underground Station

The marine sedimentary strata are spread in coastal area of Tianjin. Due to low soil strength, high underground water level and strong soil plasticity flow, instability accidents happened frequently in soft soil area. In the foundation excavation of underground station, because of stress release and change in ground water level, the differential settlement of surrounding buildings, ground crack and deformation of underground pipeline will happen. The stability of surrounding rocks in the foundation excavation of underground station has been calculated and analyzed by using numerical simulation method. The Surrounding soil deformation of foundation pit has been gotten to analyze.

scholarly journals Correction of Earth Pressure and Analysis of Deformation for Double-Row Piles in Foundation Excavation in Changchun of China

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Yijun Zhou ◽  
Aijun Yao ◽  
Haobo Li ◽  
Xuan Zheng
Keyword(s):  
Physical Model ◽  
Model Test ◽  
Large Scale ◽  
Similarity Theory ◽  
Earth Pressure ◽  
Physical Model Test ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Double Row ◽  
The Earth

In order to study the earth pressure and the deformation behavior of the double-row piles in foundation excavation, a large-scale physical model test was introduced to simulate deformation of double-row piles in foundation excavation based on the principle of similarity theory in this paper. Represented by the deep foundation pit engineering of Changchun, the strain and the displacement of the double-row piles and the earth pressure are calculated by the above-mentioned physical model test. Then a numerical simulation has been carried out to validate practicability of the physical model test. The results show that the strain and the displacement of the front-row piles are larger than the back-row piles. The earth pressure of the front-row piles appears to be “right convex,” correcting the specification of the earth pressure and putting forward the coefficient of β. The results in this paper may provide constructive reference for practical engineering.

scholarly journals Analysis of Situ Test Results of Earth Pressure and Pile Internal Force under Pile-Anchor Support in a Deep Foundation Pit in Xi’an

2022 ◽  
Vol 2148 (1) ◽  
pp. 012051
Author(s):  
Ruibin Yang ◽  
Xinsheng Li ◽  
Dongzhou Xie ◽  
Hongte Meng
Keyword(s):  
Earth Pressure ◽  
Internal Force ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Support Design ◽  
Limiting State ◽  
Obvious Effect ◽  
Deep Foundation Pit ◽  
The Earth ◽  
Monitoring Test

Abstract At present, in deep foundation pit engineering, on the one hand, practice is ahead of theory, and on the other hand, theory can not correctly reflect the actual construction process and environmental effects. In order to further study the distribution and change law of earth pressure and internal force of pile body in deep foundation pit pile-anchor supporting system, field monitoring test of earth pressure and pile body reinforcement stress was carried out. The monitoring results show that before excavation, the distribution of earth pressure has a great relationship with the layering of the soil, and it is distributed in sections along the depth. Compared with the theoretical static earth pressure, the measured data of the upper depth is relatively small; after excavation, the overall earth pressure is distributed along the depth in a “z” shape under the non-limiting state. As the excavation progresses, the magnitude of the reduction of the earth pressure varies from place to place, and the magnitude of the decrease of the soil with better properties is not large; after the excavation, the stress and earth pressure of the pile reinforcement correspond to each other, and the distribution is also nonlinear. The existence of anchor tension has an obvious effect on improving the internal force of the pile. The selected earth pressure calculation methods have some discrepancies in the calculation of the earth pressure value of the project, and they need to be further improved. The research in this paper can provide reference and reference for the calculation of earth pressure and support design of pile-anchor supported foundation pit.

The Application of Anchor Block in Large Soft Foundation Pit Excavation

2012 ◽  
Vol 170-173 ◽  
pp. 520-524
Author(s):  
Chi Ma ◽  
Guo Nan Liu ◽  
Yue Ying Liang
Keyword(s):  
Soft Soil ◽  
Rail Transport ◽  
Foundation Engineering ◽  
Foundation Pit ◽  
Soft Foundation ◽  
New Ideas ◽  
Soil Foundation ◽  
Soft Soil Foundation ◽  
Improved Design ◽  
Anchor Block

Based on pit excavation of Shenzhen Airport Rail transport hub project, combined with anchorage stress characteristics, difficulties was studied and numerical calculation for the envelope structure was undertaken. The successful application of design provides new ideas, improved design methods for super soft soil foundation engineering, which can greatly promote the application and development of anchor block in soft foundation excavation.

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