Single Micro Pile in Debris Landslide Anti-Sliding Mechanism Model Test Research

2013 ◽  
Vol 743 ◽  
pp. 237-243
Author(s):  
Qiang Cai ◽  
Ji Ming Kong ◽  
Yin Zhang
Keyword(s):  
Slip Surface ◽  
Test Results ◽  
Soil Pressure ◽  
Soil Arching ◽  
Single Row ◽  
Pile Spacing ◽  
Mechanism Model ◽  
Debris Landslide ◽  
Model Pile ◽  
Sliding Mechanism

Micro-piles are widely used because of its own advantages, but relatively few theoretical studies about its anti-slide mechanism. Firstly, the mechanical properties of the model pile into calibration tests, to get of elastoplastic session elastic modulus, were 0.69×104MPa and 0.04×104MPa.Through the different pile spacing under a single row of miniature pile reinforcement debris landslide indoor model experiment to study the micro-piles against sliding mechanism. The test results show that: different pile spacing, single row of micro-pile soil pressure mainly concentrated in the range of slip surface more than 1/3 of the pile. The smaller pile spacing, soil arching effect, the greater the micro pile skid failure critical moment, the micro pile can withstand landslide thrust the greater skid the better.

scholarly journals SOIL ARCHING AND LOAD TRANSFER MECHANISM FOR SLOPE STABILIZED WITH PILES

2012 ◽  
Vol 18 (5) ◽  
pp. 701-708 ◽  
Author(s):  
Mehmet Rifat Kahyaoglu ◽  
Okan Onal ◽  
Gökhan Imançlı ◽  
Gürkan Ozden ◽  
Arif S. Kayalar
Keyword(s):  
Load Transfer ◽  
Soil Surface ◽  
Time Lapse ◽  
Pile Head ◽  
Soil Pressure ◽  
Soil Arching ◽  
Recording Time ◽  
Pile Spacing ◽  
Stabilizing Piles ◽  
The Moment

In this study, the effects of pile spacing and pile head fixity on the moment and lateral soil pressure distribution along slope stabilizing piles are investigated. A slice from an infinitely long row of piles with fixed pile tip in an inclined sand bed was simulated with an experimental test setup. Surficial soil displacements were monitored and relative displacements between soil particles were determined by recording time-lapse images during the test in order to observe the soil arching mechanism on the soil surface. The load transfer process from moving soil to piles and behavior of soil around piles were observed and evaluated by the different test setups. It was observed that decrease in pile spacing causes an increase of load carried per pile. This behavior, which was significantly influenced by the pile head boundary conditions, can only be explained by soil arching that existed between the piles along their lengths.

scholarly journals An Experimental Study of Horizontal Bearing Capacity of Vertical Steel Floral Tube Micropiles with Double Grouting

2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
Kaiyang Wang ◽  
Yanjun Shang
Keyword(s):  
Bearing Capacity ◽  
Large Scale ◽  
Slip Surface ◽  
Bending Moment ◽  
Shear Capacity ◽  
Soil Reinforcement ◽  
Scale Model ◽  
Soil Pressure ◽  
Floral Tube ◽  
Grouting Pressure

This paper examines the performance of a novel technology, vertical steel floral tube micropiles with double grouting. It is the combination of micropile technology and double grouting technology. A large-scale model tank was applied to impart horizontal bearing capacity, and the slope soil pressure and flexural performance of the micropile were investigated under four experimental conditions. The peak grouting pressure during the double grouting process was defined as the fracturing pressure of the double grouting, and it was positively correlated to the interval time between first grouting and secondary grouting. Compared with traditional grouting, double grouting increased the horizontal bearing capacity of the single micropile with the vertical steel floral tube by 24.42%. The horizontal bearing capacity was also 20.25% higher for the structure with three micropiles, compared with a 3-fold value of horizontal sliding resistance. In the test, the maximum bending moment acting on the pile above the sliding surface was located 2.0–2.5 m away from the pile top, and the largest negative bending moment acting on the pile below the slip surface was located 4.0 m away from the pile top. The ultimate bending moment of the single pile increased by 12.8 kN·m with double grouting, and the bending resistance increased by 96.2%. The experimental results showed that the double grouting technology significantly improved the horizontal bearing capacity of the micropile with the steel floral tube, and the soil reinforcement performance between piles was more pronounced. Also, the shear capacity and the flexural capacity were significantly improved compared with the original technology.

Determination of Spacing between Anchored Piles in Row for Deep Foundation Pit

2012 ◽  
Vol 204-208 ◽  
pp. 2736-2739
Author(s):  
Guang Qian Du ◽  
Shi Jie Wang ◽  
Yan Ting Qin ◽  
Chang Zhi Zhu
Keyword(s):  
Strength Criterion ◽  
Strength Analysis ◽  
Soil Arching ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Pile Spacing ◽  
Soil Arch ◽  
Uniformly Distributed Loads

Based on the pile - anchor structure soil between piles,the unified strength theory is introdued in the strength analysis of soil arching between the piles, and parabolic soil arching computational model is uniformly distributed loads ,which are given to meet the soil between piles arch static equilibrium conditions and intensity of conditions , pile spacing formula. Compared with calculations based on the pile spacing of the Mohr-Coulomb strength criterion , the proposed method can consider the contribution of the intermediate principal stress on the strength of the soil arch , the results are more in line with the actual characters of the supporting structure .

Influence of loading rate on the capacity of a model pile in clay

1995 ◽  
Vol 32 (2) ◽  
pp. 364-368 ◽  
Author(s):  
Robert G. Horvath
Keyword(s):  
Loading Rate ◽  
Axial Loading ◽  
Displacement Transducer ◽  
Test Methods ◽  
Point Load ◽  
Test Results ◽  
Loading Test ◽  
Normal Loading ◽  
Model Pile ◽  
Rate Of Loading

Loading tests were carried out on a model pile embedded in clay to examine the influence of rate of loading on the capacity of the pile. The pile was loaded to failure using constant rate of penetration (CRP), quick maintained loading (QML), and quick continuous loading (QCL) methods of loading. The QCL test models the Statnamic loading test, which has been recently developed in Canada. The CRP tests were used as a reference, and the results were normalized using the CRP test results. The durations of the QML and QCL tests varied from approximately 0.1 s to 17 min, which are significantly faster than normal loading rates. Applied loads and point load were measured using load cells, and top displacement was measured using a displacement transducer. The test results showed an increase in pile capacity with increased rate of loading. Damping was found to be significant for the QCL tests (duration = 0.1 s) and negligible for the QML tests (duration ≥ 10 s). Correcting the results of the QCL tests for damping, using the equilibrium point method developed for Statnamic testing, greatly improved the correlation of the QCL and QML test results. Key words : model piles, axial loading, loading rate, clay, laboratory study, test methods.

scholarly journals Pile-Spacing Calculation of Anti-Slide Pile Based on Soil Arching Effect

2020 ◽  
Vol 2020 ◽  
pp. 1-6 ◽  
Author(s):  
Guangfu Chen ◽  
Liangchao Zou ◽  
Qing Wang ◽  
Guodong Zhang
Keyword(s):  
Load Capacity ◽  
Limit Equilibrium ◽  
Interaction Mechanism ◽  
Soil Arching ◽  
Pile Spacing ◽  
Arching Effect ◽  
Soil Arching Effect ◽  
Engineering Designs ◽  
Practical Engineering ◽  
The Difference

Anti-slide pile is one of the most frequently used measures in landslide control globally. Pile-spacing has always been determined by the load capacity of single piles or according to engineering empirical experience. Many engineering practices and laboratory experiments show that the soil arching effect exists in landslide control with anti-slide piles. In this study, we aim to calculate pile-spacing in terms of the soil arching effect. We investigated the pile-soil interaction mechanism and propose that, at the limit, the pile-back soil arch resists landslide thrust only. According to Mohr–Coulomb strength theory and limit equilibrium theories, we derived a new pile-spacing calculation equation. We verified the derived pile-spacing calculation equation with real projects. The calculated results are similar to those of practical engineering designs, in which the difference is within 10%. The equation can be used in anti-slide pile preliminary design. This study can be a reference for pile-spacing calculation based on the soil arching effect.

scholarly journals TRANSMISSION OF RANDOM WAVES THROUGH PILE BREAKWATERS

1986 ◽  
Vol 1 (20) ◽  
pp. 169 ◽  
Author(s):  
Clifford L. Truitt ◽  
John B. Herbich
Keyword(s):  
Random Waves ◽  
Pile Spacing ◽  
Transmission Coefficients ◽  
Pile Diameter ◽  
Model Pile ◽  
Incident Waves ◽  
Good Agreement ◽  
Monochromatic Waves

Several previous investigators have conducted experiments leading to expressions for predicting the transformation of waves passing through closely-spaced pile breakwaters. The present study extends those earlier experiments using monochromatic waves to the case of a spectrum of random waves. Records of incident waves and of waves after transmission through a model pile breakwater were compared to determine a coefficient of transmission. Results are presented for several cases of pile spacing and pile diameter. Good agreement is found between observed transmission coefficients and those predicted using the expression proposed by Hayashi et al. (1966).

Time-dependent displacement behaviour of model adfreeze and grouted piles in saline frozen soils

1994 ◽  
Vol 31 (3) ◽  
pp. 395-406 ◽  
Author(s):  
K.W. Biggar ◽  
D.C. Sego
Keyword(s):  
Field Studies ◽  
Frozen Soil ◽  
Silty Sand ◽  
Time Dependent ◽  
Test Results ◽  
Model Pile ◽  
Laboratory Test Results ◽  
Load Carrying ◽  
Pile Deformation

The findings of a laboratory study on the time-dependent displacement of model piles in saline frozen soil are reported. The short-term time-dependent pile deformation in ice-poor saline silty sand was best described using a simple power law of time, whereas the long-term time-dependent deformations were best described using a flow law formulation similar to that used to describe the long-term time-dependent deformation of ice or ice-rich permafrost. The use of cementitious grout as a backfill resulted in doubling of the pile load carrying capacity for a given displacement rate. The laboratory test results compare well with other laboratory and field studies. Key words : frozen soil, saline, model pile, time-dependent deformation, sand backfill, grout.

Calculation of Lateral Soil Pressure at the Hydraulic Construction and its Sustainability on the Stone Bed

2020 ◽  
Vol 1006 ◽  
pp. 149-157
Author(s):  
Irina A. Karpiuk ◽  
Vasyl M. Karpiuk ◽  
F.R. Karpiuk
Keyword(s):  
Stress Condition ◽  
Slip Surface ◽  
Normal Pressure ◽  
Soil Pressure ◽  
Elastic Zone ◽  
Technical Theory ◽  
Strip Loading ◽  
Internal Side ◽  
Definition Of ◽  
Ultimate Condition

The engineering method of analysis of pressure of a ground on flat walls is offered at presence of combine strip superficial loading in view of seismic influences. It is recommended to determine a situation of an internal slip surface dividing an elastic zone from area of limiting balance, on the basis of the technical theory of the ultimate stress condition. Proceeding from a situation of an internal and external slip plane, size of strip loading on the fill, the pressure of a ground which is taking place in an ultimate condition, on an internal slip surface of is determined on developed by P. Yakovlev to the specified Coulomb's method [1], and on an internal side of a retaining structure on the basis of the Boussinesq decision. In comparison with the earlier developed way it is offered specified according to the Boussinesq theory a method of definition of pressure transmitted by bed on a ground of the basis and, as a consequence more reasonable definition of safety factor of stability of a structure. Thus, curvilinear normal pressure diagram in a ground under a sole of lay is replaced on isosides trapeziform.

Soil Arching over Deeply Buried Thermoplastic Pipe

2003 ◽  
Vol 1849 (1) ◽  
pp. 109-123 ◽  
Author(s):  
Shad M. Sargand ◽  
Teruhisa Masada
Keyword(s):  
Strain Gauge ◽  
Bending Stiffness ◽  
Field Soil ◽  
Stiffness Parameter ◽  
Soil Pressure ◽  
Buried Pipe ◽  
Soil Arching ◽  
Pressure Cell

Soil arching associated with buried thermoplastic pipe is discussed. First, the soil arching phenomenon is described. Then two different approaches are mentioned from the literature to represent the degree of soil arching (or vertical arching factor). The elastic solutions of Burns and Richard are revisited to derive expressions for the vertical soil arching factor for buried pipe. Comparison of the elastic solutions and field soil pressure cell readings reveals the importance of incorporating a bending stiffness parameter. With this finding, the AASHTO method for calculating the load on buried pipe is evaluated against the elastic solutions. The analysis reveals that the AASHTO method is conservative, overestimating the load on thermoplastic pipe by up to 30%. Further evidence to support the finding is found within the strain gauge readings taken on the pipe walls in the field. Therefore, alternative equations derived directly from the elastic solutions are recommended to predict the load on buried thermoplastic pipe instead of the AASHTO method.

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