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.

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 A Theoretical Solution for Pile-Supported Embankment with a Conical Pile-Head

2019 ◽  
Vol 9 (13) ◽  
pp. 2658 ◽  
Author(s):  
Chengfu Zhang ◽  
Minghua Zhao ◽  
Shuai Zhou ◽  
Zeyu Xu
Keyword(s):  
Load Transfer ◽  
Cell Model ◽  
Theoretical Solution ◽  
Model Parameters ◽  
Pile Head ◽  
Soil Arching ◽  
Arching Effect ◽  
Soil Arching Effect ◽  
Comparative Results ◽  
Pile Supported Embankment

This paper, with a focuses on the pile-supported embankment with a conical pile-head, proposes a theoretical solution which incorporates all the load transfer mechanisms, namely the soil arching effect, the pile–soil interaction, and the support from the substratum, whilst an improved cylindrical unit cell model is introduced to analyze the soil arching effect. The theoretical solution has been verified via numerical analysis and a literature method. The comparative results indicate that the proposed theoretical solution can effectively evaluate the pile-supported embankment with a conical pile-head. Furthermore, parametric studies have also been conducted to analyze the effect of model parameters on the load sharing ratio (ne), the pile–soil stress ratio (n), and the pile shaft friction.

Comparison of the Bidirectional Load Test with the Top-Down Load Test

2005 ◽  
Vol 1936 (1) ◽  
pp. 108-116 ◽  
Author(s):  
Oh Sung Kwon ◽  
Yongkyu Choi ◽  
Ohkyun Kwon ◽  
Myoung Mo Kim
Keyword(s):  
Load Transfer ◽  
Measurement Data ◽  
Load Test ◽  
Load Testing ◽  
Pile Head ◽  
Top Down ◽  
Simple Method ◽  
Testing Method ◽  
Settlement Behavior ◽  
Cell Test

For the past decade, the Osterberg testing method (O-cell test) has been proved advantageous over the conventional pile load testing method in many aspects. However, because the O-cell test uses a loading mechanism entirely different from that of the conventional pile loading testing method, many investigators and practicing engineers have been concerned that the O-cell test would give inaccurate results, especially about the pile head settlement behavior. Therefore, a bidirectional load test using the Osterberg method and the conventional top-down load test were executed on 1.5-m diameter cast-in-place concrete piles at the same time and site. Strain gauges were placed on the piles. The two tests gave similar load transfer curves at various depth of piles. However, the top-down equivalent curve constructed from the bidirectional load test results predicted the pile head settlement under the pile design load to be approximately one half of that predicted by the conventional top-down load test. To improve the prediction accuracy of the top-down equivalent curve, a simple method that accounts for the pile compression was proposed. It was also shown that the strain gauge measurement data from the bidirectional load test could reproduce almost the same top-down curve.

scholarly journals Near-surface real-time seismic imaging using parsimonious interferometry

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sherif M. Hanafy ◽  
Hussein Hoteit ◽  
Jing Li ◽  
Gerard T. Schuster
Keyword(s):  
Fluid Flow ◽  
Real Time ◽  
Temporal Resolution ◽  
Seismic Imaging ◽  
Time Lapse ◽  
Rock Properties ◽  
Recording Time ◽  
Near Surface ◽  
Arrival Times ◽  
Order Of Magnitude

AbstractResults are presented for real-time seismic imaging of subsurface fluid flow by parsimonious refraction and surface-wave interferometry. Each subsurface velocity image inverted from time-lapse seismic data only requires several minutes of recording time, which is less than the time-scale of the fluid-induced changes in the rock properties. In this sense this is real-time imaging. The images are P-velocity tomograms inverted from the first-arrival times and the S-velocity tomograms inverted from dispersion curves. Compared to conventional seismic imaging, parsimonious interferometry reduces the recording time and increases the temporal resolution of time-lapse seismic images by more than an order-of-magnitude. In our seismic experiment, we recorded 90 sparse data sets over 4.5 h while injecting 12-tons of water into a sand dune. Results show that the percolation of water is mostly along layered boundaries down to a depth of a few meters, which is consistent with our 3D computational fluid flow simulations and laboratory experiments. The significance of parsimonious interferometry is that it provides more than an order-of-magnitude increase of temporal resolution in time-lapse seismic imaging. We believe that real-time seismic imaging will have important applications for non-destructive characterization in environmental, biomedical, and subsurface imaging.

scholarly journals Load Transfer by Soil Arching in Pile-Supported Embankments

2007 ◽  
Vol 47 (5) ◽  
pp. 833-843 ◽  
Author(s):  
Won Pyo Hong ◽  
Jae Ho Lee ◽  
Kwang Wu Lee
Keyword(s):  
Load Transfer ◽  
Soil Arching

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 .

scholarly journals PERANCANGAN FONDASI TIANG PANCANG PADA TANAH BERPOTENSI LIKUIFAKSI DI SULAWESI

2020 ◽  
Vol 3 (3) ◽  
pp. 865
Author(s):  
Markus Jusuf ◽  
Aksan Kawanda
Keyword(s):  
Soil Layer ◽  
Cyclic Stress ◽  
Lateral Spreading ◽  
Soil Pressure ◽  
Spreading Effect ◽  
Cyclic Resistance ◽  
Cyclic Resistance Ratio ◽  
Liquefied Soils ◽  
Moment Effect ◽  
The Moment

ABSTRACTIndonesia is a country located in the most active earthquake paths in the world. This makes Indonesia prone to earthquakes and has the potential to experience liquefaction. Liquefaction can cause pile failure, so several things need to be considered in designing piles on potentially liquefied soils. One project in Sulawesi has a profile of uniform grained saturated soil that is susceptible to liquefaction. Two things that need to be considered in the design of piles on potentially liquefied soils is to ignore the capacity of pile friction and calculate the moment due to lateral spreading effects. Calculation of liquefaction potential is done by comparing the ratio of the cyclic stress and the cyclic resistance ratio and is compared by four other methods namely: the Seed et al. (2003), Tsuchida (1970), Seed et al. (2003), and Bray & Sancio (2004). The lateral spreading effect is calculated by referring to the JRA Code where the liquefied soil layer gives pressure to the pile at 30% of the overburden stress and the soil layer above the liquefied soil gives passive soil pressure to the pole. The moment effect caused by lateral spreading results in the addition of dimensions or number of poles.Keywords: liquefaction; lateral spreading; bearing capacity; JRA Code; pile foundationABSTRAKIndonesia adalah negara yang terletak di jalur gempa teraktif di dunia. Hal ini menyebabkan Indonesia rawan gempa dan memiliki potensi untuk mengalami likuifaksi. Likuifaksi dapat menyebabkan kerusakan/kegagalan struktur yang sangat merugikan, sehingga perlu diperhatikan beberapa hal dalam merancang tiang pada tanah berpotensi likuifaksi. Salah satu proyek di Sulawesi memiliki profil tanah pasir berbutir seragam dan jenuh air yang memiliki potensi likuifaksi. Dua hal yang perlu diperhitungkan dalam perancangan tiang pada tanah berpotensi likuifaksi adalah mengabaikan daya dukung friksi tiang dan memperhitungkan momen akibat efek lateral spreading. Perhitungan potensi likuifaksi dilakukan dengan membandingkan rasio tegangan siklik (CSR) dan rasio hambatan siklik (CRR) serta dibandingkan dengan empat metode lainnya yaitu: metode Seed et al. (2003), Tsuchida (1970), Seed et al. (2003), dan Bray & Sancio (2004). Daya dukung aksial pada tiang pancang mengalami pengurangan 32% akibat lapisan tanah yang terlikuifaksi. Efek lateral spreading dihitung dengan acuan JRA Code dimana lapisan tanah terlikuifaksi memberikan tekanan ke tiang sebesar 30% dari tegangan overburden dan lapisan tanah di atas tanah terlikuifaksi memberikan tekanan tanah pasif ke tiang. Efek momen yang diakibatkan oleh lateral spreading mengakibatkan penambahan dimensi ataupun jumlah tiang.Kata kunci: likuifaksi; lateral spreading; daya dukung; JRA Code; fondasi tiang    

Numerical investigation of the monotonic drained lateral behaviour of large diameter rigid piles in medium dense uniform sand

Géotechnique ◽  
2021 ◽  
pp. 1-39
Author(s):  
Huan Wang ◽  
M. Fraser Bransby ◽  
Barry M. Lehane ◽  
Lizhong Wang ◽  
Yi Hong
Keyword(s):  
Numerical Investigation ◽  
Load Transfer ◽  
Large Diameter ◽  
Offshore Wind ◽  
Soil Pressure ◽  
Lateral Capacity ◽  
Pile Diameter ◽  
Centrifuge Tests ◽  
Lateral Response ◽  
Loading Eccentricity

This paper presents a numerical investigation of the monotonic lateral response of large diameter monopiles in drained sand with configurations typical of those employed to support offshore wind turbines. Results from new centrifuge tests using instrumented monopiles in uniform dry sand deposits are first presented and used to illustrate the suitability of an advanced hypoplastic constitutive model to represent the sand in finite element analyses of the experiments. These analyses are then extended to examine the influence of pile diameter and loading eccentricity on the lateral response of rigid monopiles. The results show no dependency of suitably normalized lateral load transfer curves on the pile diameter and loading eccentricity. It is also shown that, in a given uniform sand, the profile with depth of net soil pressure at ultimate lateral capacity is independent of the pile diameter because of the insensitivity of the depth to the rotation centre for a rigid pile. A normalization method is subsequently proposed which unifies the load-deflection responses of different diameter rigid piles at a given load eccentricity.

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 The Research on a Confined Modeling Method of the Effect of Deformable Ground Soil and Crawler Board

2018 ◽  
Vol 237 ◽  
pp. 02011
Author(s):  
LV Wei ◽  
Zhong-xin LI ◽  
LOU Peng
Keyword(s):  
Maximum Stress ◽  
Ground Deformation ◽  
Soil Mechanics ◽  
Soil Surface ◽  
Physical Significance ◽  
Soil Parameters ◽  
Soil Test ◽  
Analysis Model ◽  
Soil Pressure ◽  
Vehicle Mobility

There is a great relationship between the passing capacity of vehicles on the ground deformation road and the properties of confined and shear of ground soil, so it is necessary to establish a model that can reflect the soil pressure of the deformation. Physical significance of classic soil pressure experience parameters model is indeterminate, it was generally obtained by a lot of specific soil test. In this paper a new analysis model was built though introducing the maximum stress value of the crawler board and soil surface on basis of a kind of existing analysis model. This model reveals the relations among the confined characteristics of soil, soil parameters and the geometry of confined crawler board. These soil parameters can be obtained through the conventional soil mechanics test without a large number of specific soil test. Through the contrast experiment and predictions results, this model can effectively predict the sinkage of ground soil under the load, and provide a theory basis for the prediction of vehicle mobility.

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