scholarly journals Influence of skirt reinforcement in passive zone on deformation of excavation

2020 ◽  
Vol 198 ◽  
pp. 02012
Author(s):  
Peng-fei CHEN ◽  
Xiao-nan GONG
Keyword(s):  
Lateral Displacement ◽  
Soft Soil ◽  
Bending Moment ◽  
Protection Scheme ◽  
Soil Mixing ◽  
Set Up ◽  
The Stability ◽  
Cement Soil ◽  
Plaxis 3D ◽  
Passive Area

In the design of the excavation protection scheme in the soft soil area, it is often necessary to set up cement-soil mixing piles in the passive area. In this way, the stability requirements of the excavation can be met, and the lateral displacement of the retaining pile can be greatly restricted. This paper uses PLAXIS 3D to establish a excavation model in a soft area, and discusses the influence of various parameters of the passive zone mixing pile on the deformation and force of the excavation. Within a certain range, as the cohesive force or secant modulus or reinforcement width or depth of the reinforcement area increases, the lateral displacement and settlement outside the pit will decrease. But when it exceeds a certain range, the decreasing trend becomes very slow. With the increase of the four parameters of the reinforcement zone, bending moments in opposite directions appear below the bottom of the excavation. Moreover, the value of the bending moment is getting larger and larger. Therefore, considering the force, it is not that the wider and deeper the reinforced zone is, the more advantageous is.

Study and Analysis on Pile-Soil Stress Ratio of the Composite Foundation of Cement-Soil Mixing Pile under Flexible Foundation

2011 ◽  
Vol 335-336 ◽  
pp. 1145-1150
Author(s):  
Xiao Rong Yang ◽  
Lei Yu Zhang ◽  
Hai Chao Li ◽  
Li Ying Dong
Keyword(s):  
Stress Ratio ◽  
Soft Soil ◽  
Composite Foundation ◽  
Soil Mixing ◽  
Soil Stress ◽  
Soil Foundation ◽  
Soft Soil Foundation ◽  
Flexible Foundation ◽  
Cement Soil ◽  
Friction Pile

In order to analyze the characteristics of pile-soil stress ratio of the composite foundation of cement-soil mixing pile under flexible foundation, this paper points out the displacement mode of friction pile; According to the deformation characteristic of friction pile, ascertain the neutral point of composite foundation. And this paper also derives the exact formula about length-stress ratio which addresses the problem of soft soil foundation according to the deformation co-ordination conditions of the pile composite foundation. The calculation of actual example proves that the formula about pile-soil stress ratio is in accordance with actual measurement number. The pile-soil stress ratio which addresses the problem of soft soil foundation is generally between 2~4. If other conditions keep invariable, pile-soil stress ratio become big when cushion modulus become big. Cushion modulus effect the length-stress ratio greatly.

Construction Technique of Cement-Soil Mixing Anchor in Foundation Pit in Soft Soil Area

2011 ◽  
Vol 261-263 ◽  
pp. 1784-1788
Author(s):  
Gan Bin Liu ◽  
Rong Hua Ye ◽  
Li Xu ◽  
Xue Yi Shen
Keyword(s):  
Soft Soil ◽  
Drill Pipe ◽  
Soft Clay ◽  
Mechanical Equipment ◽  
Pullout Capacity ◽  
Foundation Pit ◽  
Construction Technique ◽  
Soil Mixing ◽  
Design Engineers ◽  
Cement Soil

In this paper, the construction technique of a new soil anchor-the cement-soil mixing anchor, which is applicable in the area of soft clay, is introduced. During the construction of the anchor, the drill pipe and blade is served as a reinforced body and formed an anchorage body with the cement-soil body. The material and making, technics parameters, mechanical equipment and construction requirement of the cement-soil mixing anchor are presented firstly. Then, the uplift tests of the cement-soil mixing anchor are carried out, and the ultimate pullout force which is 1.6 times greater than that of the soil nailing in the same condition is obtained. At last, an application of the cement-soil mixing anchor in a foundation pit is given. The test results shown that the application of the cement-soil mixing anchor can reach the expected reinforcement effect. Therefore, this framework can then be used by design engineers to more confidently estimate the pullout capacity of cement-soil mixing anchors under tension loading.

The Research on Applied of Cement-Soil Mixing Method Reinforcing Shallow Soft-Soil Foundation in Yinchuan Distric

2013 ◽  
Vol 477-478 ◽  
pp. 572-576 ◽  
Author(s):  
Cai Xia Ma
Keyword(s):  
Soft Soil ◽  
Economic Benefits ◽  
Influential Factors ◽  
Composite Foundation ◽  
Soil Mixing ◽  
Mixing Method ◽  
Points Of View ◽  
Soil Foundation ◽  
Soft Soil Foundation ◽  
Cement Soil

Through tests and application, analyzes influential factors & reinforcement effect and application prospects & economic benefits of cement-soil mixing composite foundation, propounds some points of view for stabilizing & reinforcement soft-soil foundation by cement-soil mixing method especially in Yinchan District combined with constructive situation

Study of Safety Influence Factor of Bridge Substructure in Loess Gulch

2012 ◽  
Vol 546-547 ◽  
pp. 89-96
Author(s):  
Jin Wei ◽  
Zhong Ju Feng ◽  
Feng Ma
Keyword(s):  
Soil Erosion ◽  
Debris Flow ◽  
Pile Foundation ◽  
Influence Factor ◽  
Lateral Displacement ◽  
Bending Moment ◽  
Zero Point ◽  
Internal Force ◽  
Prevention Measures ◽  
The Stability

In this paper, the geology characteristics of loess gulch area were summarized. The mechanical models of the influence of landslide, debris flow and soil erosion on the safety of the pile foundation were created. The influence of the geology casualty on the safety of the pile foundation were analyzed. The analyses showed, when the pile foundation located the varied position of the loess gulch, the influence of soil erosion on the pile foundation character (acting force of pile side, free length of the pile, the first zero point position of the flexure curve, drawdown of the maximum bending moment, the increment of the lateral displacement, the drawdown of the lateral bearing capacity, the drawdown of the stability, etc.) were strikingly different. The calculation method of the pile and pier internal force was put forward under the function of landslide thrust and pressing force of debris flow. The corresponding prevention measures to different influencing factors were presented in the end.

scholarly journals Modeling Riverbank Slope Reinforcement Using Anti-Slide Piles with Geocells

2021 ◽  
Vol 9 (4) ◽  
pp. 394
Author(s):  
Zhen Liu ◽  
Pengzhen Liu ◽  
Cuiying Zhou ◽  
Yasheng Li ◽  
Lihai Zhang
Keyword(s):  
Lateral Displacement ◽  
Measurement Data ◽  
Bending Moment ◽  
Theoretical Models ◽  
Friction Mechanism ◽  
Support Mechanism ◽  
Vertical Support ◽  
Parametric Studies ◽  
The Stability ◽  
Vertical Action

Geocells are increasingly used in engineering applications, but the design of riverbank slope reinforcements that use only geocells limits reinforcement performance. Moreover, the design and use of anti-slide piles with geocells are mainly based on experiences that are unsupported by theoretical models. In this paper, by combining the confinement effect and vertical action mechanism of geocells, the horizontal friction mechanism of the geocell layer and the vertical support mechanism of piles, a theoretical model of riverbank slope reinforced by anti-slide piles with geocells was constructed. In addition, to describe the mechanical behavior of a riverbank slope reinforced by anti-slide piles with geocells, the slip-resisting mechanism of the anti-slide pile with interaction between geocells and their internal filler is considered in the model. Furthermore, to investigate the influence of changes in water level on riverbank slope stability, the developed model takes into account settlement, lateral displacement, pile bending moment and pile axial force. The model predications were validated by the field measurement data. The results from a series of parametric studies show that the use of anti-slide pile and geocells can effectively reduce the settlement and the lateral displacement of a riverbank slope. The developed model could contribute to an optimal design of anti-slide pile with geocells for enhancing the stability of a riverbank slope.

Study on the Law of Cement-Soil Mixing Pile Composite Foundation Settlement in Ancient Tower Translocation Project

2017 ◽  
Vol 730 ◽  
pp. 463-472
Author(s):  
Dong Fan Shang ◽  
Tie Cheng Wang ◽  
Wan Ming Qiang ◽  
Lei Qiang Miao
Keyword(s):  
Retention Time ◽  
Soft Soil ◽  
Composite Foundation ◽  
Design Solution ◽  
Foundation Settlement ◽  
Soil Mixing ◽  
Soil Foundation ◽  
Soft Soil Foundation ◽  
Cement Soil ◽  
Translocation Speed

Longxi Tower translocation project is the first case of high-rise ancient tower structure translocation on soft soil foundation in China. Foundation treatment protocol and building materials are essential to control soft soil foundation settlement. Depending on Longxi Tower translocation project, firstly this thesis analyzed and confirmed control factors that impact foundation settlement and deformation; then combing with project experience, it selected cement soil mixing pile composite foundation method to treat soft soil foundation; and finally it confirmed the optimal solution to treat cement soil mixing pile composite foundation through analyzing the settlement law of cement soil mixing pile composite foundation. The analysis indicated that cement soil mixing pile composite foundation settlement are obviously impacted by translocation speed and retention time; foundation settlement and deformation level increase as translocation speed decreases and retention time increases; in the case that foundation settlement difference is not beyond 1/1000 of half the distance of track beams at the bottom of building, a treatment solution was made by analyzing how cement soil mixing pile settlement changes as translocation speed, retention time and other factors. The result showed that this treatment solution saved 42% of project cost more than the previous design solution. The research result of this thesis could be taken as a reference for the future similar projects.

Application of Cement-Soil Mixing Pile with Bearing Load Plate

2012 ◽  
Vol 170-173 ◽  
pp. 3199-3202
Author(s):  
Peng Li He
Keyword(s):  
Soft Soil ◽  
Soil Layer ◽  
Construction Technology ◽  
Bearing Plate ◽  
Soil Mixing ◽  
Soil Cement ◽  
Bearing Load ◽  
Good Potential ◽  
Layered Ground ◽  
Cement Soil

In order to treat efficiently with the soft multi-layers in the middle of ground, the improved cement-soil double mixed pile is developed and the pile diameter is enlarged in the soft soil layer depth to form the cement-soil mixed column with bearing load plate. The installation mechanism, deep mixing machine, and pile installation procedure of the soil-cement mixed pile with bearing plate is presented. The field test results show that the cement-soil mixing pile with bearing load plate construction technology can ensure the cement mix content and mixing uniformity. The pile strength is greatly higher than conventional cement-soil pile, so it can be used to improved soft multi-layered ground economically and effectively, and it has a good potential application for practice.

Mechanical Stability Analysis of Subsea Wellhead for Deepwater Production to Earthquake Load

2010 ◽  
Vol 44-47 ◽  
pp. 1061-1065
Author(s):  
Wen Sheng Xiao ◽  
Xiu Juan Lin ◽  
Hong Yan Wang
Keyword(s):  
Mechanical Stability ◽  
Lateral Displacement ◽  
Bending Moment ◽  
Horizontal Displacement ◽  
Lateral Force ◽  
Angular Distortion ◽  
Soil Reaction ◽  
Seismic Load ◽  
Earthquake Load ◽  
The Stability

Subsea wellhead for deepwater production subjects to axial force, lateral force and bending moment under the seismic loading, the effect of subsea christmas tree and casing string’s gravity. Joint action of these forces makes it is possible that horizontal displacement exceeds the limitation and thus loses the stability. A mechanical analytical model of subsea wellhead for deepwater production is established on the basis of the pile foundation theories and material mechanics, the seismic load and behavior between casing string and formation are considered. The analyses on lateral displacement, angular distortion, bending moment and shear force show that the affection of lateral load is focus on the upper section of casing string, and the lateral displacement of subsea wellhead for deepwater production increases along with earthquake load and thus decreases stability. The stability improves notably with the increase of coefficient of soil reaction. Therefore it is necessary to obtain the on-the-spot geological data in shallow formation. The wellhead stability may be improved to different degrees by taking measures such as minimizing axial load, enhancing the conductor bending strenth, increasing the depth of the casing string in soil, reducing the outcropping length of the casing string.

scholarly journals Mitigating effect of embankment to adjacent pipe with CDM columns

2021 ◽  
Vol 263 ◽  
pp. 02053
Author(s):  
Tiep Duc Pham ◽  
Nang Duc Bui ◽  
Quang Trong Vu ◽  
Huan Thanh Duong ◽  
Hieu Chi Phan
Keyword(s):  
Lateral Displacement ◽  
Soft Soil ◽  
Bending Moment ◽  
Internal Force ◽  
Fe Model ◽  
Large Area ◽  
Long Distance ◽  
Buried Structures ◽  
Input Variables ◽  
The Cost

Pipelines are valuable infrastructures that covering a large area or expanding to long distance for the transporting function. This leads to the variety of loads and effects applied on such buried structures. A thread to pipeline integrity is the construction of the embankment on the soft soil which leads to the displacement of the pipe adjacent to the slope. This displacement will effect to the increase of internal force or causing failure of the near-by pipes. The use of concrete pile to improve the soil properties may be a solution; however, the cost for this is expensive. To propose an alternative solution for the problem, this study uses a system of cement deep mixing, CDM, columns as the solution for protecting the pipe. A simple 2D Finite Element, FE, model using Plaxis software has been established based on the equivalent soil approach which considering the CDM columns and their surrounding soil as an unified soil. The effectiveness of the proposed solution has been numerically investigated and proven. The lateral displacement of pipe and the maximum ring bending moment and other internal forces are significantly reduced with the appearance of the CDM columns. The selective parametric study has been implemented revealing the critical input variables are the distance of pipe to the slope and the length of the CDM column.

Mechanism analysis and application of cement-soil mixing pile in soft roadbed treatment

2018 ◽  
Vol 28 (2) ◽  
pp. 161-172
Author(s):  
JUNHUI LUO ◽  
XIANLIN LIU ◽  
HAIFENG HUANG ◽  
DECAI MI ◽  
DEQIANG CHE
Keyword(s):  
Mechanism Analysis ◽  
Soil Mixing ◽  
Cement Soil
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