Presence Of Piles Research Articles

Experimental Study on Seismic Response of Underground Tunnel–Soil–Piled Structure Interaction Using Shaking Table in Loose Sand

The seismic response of structures can have a significant impact on adjacent structures’ response. Although several numerical studies have been applied in the field of tunnel–soil–pile interaction systems, there is a lack of experimental research specifically focused on the effects of this interaction on tunnel cross-section deformation and the existence of structure on encircling soil response. In this study, shaking table tests were conducted to examine the seismic response of a tunnel and the surrounding soil when an eight-story structure with piles was located in the vicinity of the tunnel. Four series of physical models were analyzed, including free-field soil (S), tunnel–soil (TS), soil-piled structure (SP), and tunnel–soil-piled structure (TSP), under sinusoidal vibration at three frequencies on loose sand. According to the results, the tunnel significantly impacts the surrounding soil response during seismic excitation with reduced acceleration at the tunnel invert and increased acceleration at the tunnel crown. In the TSP model, applied frequency affects the recorded acceleration amplitude at the tunnel invert. Although acceleration amplitude decreases at 3 Hz frequency excitation compared to the free field model, 8 Hz excitation resulted in bigger values in tunnel invert. Displacements are higher at the tunnel crown, indicating tunnel-induced soil deformation and maximum shear strain concentrated near the tunnel crown. The tunnel cross-section exhibited oval shape changes, with higher forces on the tunnel crown in the presence of piles.

Modeling Tests on Lateral and Overturning Resistance according to Pile Arrangement for Wind Turbine Foundation

In this study, the lateral resistance and bending moment of a wind turbine foundation reinforced with piles on the bedrock were evaluated through modeling tests considering the cross-sectional size and presence of piles. The lateral resistance of a small foundation (16 m) with piles was found to be 1.84 times greater than that of the existing wind turbine foundation (20 m). After installing eight piles in the wind power turbine foundation, the outer and inner circles were compared, and the lateral resistance at the outer circle with piles was found to be the largest. Moreover, the lateral resistance force was similar for the series, parallel, and diagonal arrangements of six piles. The bending moment increased based on the order of the front, right, and back rows. The maximum bending moment of the pile for the front row was observed at the interface between the wind turbine foundation and rubble bed, while that for the right and back rows was observed at the interface between the rubble layer and bedrock.

Long-term outcome of ligation of inter-sphincteric fistula tract (LIFT) for management of trans-sphincteric anal fistula

BackgroundAfter abscess formation, an anal fistula is a common consequence, with crypto-glandular infection being the most commonly accepted causative cause. The goal of this study was to see how well closure of the inter-sphincteric fistula tract affects the outcome of trans-sphincteric fistula surgery. MethodsPatients with perianal trans-sphincteric fistulas who underwent ligation of inter-sphincteric fistula tract (LIFT) were studied prospectively in this cohort study. All patients had the identical anesthetic approach, followed by LIFT with two years’ follow-up. Resultslength of the fistulous tract had a substantial effect on the result. The presence of piles with fistula among the studied patients has no effect on the outcome. Mean operative time was 36.2 min and post operative pain was mild in most patients and concomitant anal fissure or piles has no effect on final result of LIFT procedure The mean time for wound healing was four weeks. Three patients had hidradenitis suppurativa and no any unusual histopathology results shown in the excised parts. ConclusionLIFT was an effective and straightforward sphincter-preserving technique in treating simple trans-sphincteric anal fistulas with excellent long-term control of trans-sphincteric fistula. More similar studies with a large number of patients are still needed to assess this surgical technique for trans-sphincteric fistula.

Lateral and Overturning Resistance of Wind Turbine Foundations Reinforced with Piles on Bedrock by Modelling Experiments

This study evaluated the lateral and overturning resistance of wind turbine foundations reinforced with piles on bedrock through model experiments. In particular, changes in lateral and overturning resistance of wind turbine foundations were analyzed according to cross-sectional size and the presence of piles of wind turbine foundations. As a result, by reducing the cross-section, the lateral resistance of the pile-reinforced wind turbine foundation was compared to the existing wind turbine foundation with large cross-sections and was shown to be 1.68 times greater. In the case of vertical displacements affecting overturning, the safety of overturning was also greater, as the vertical displacement of the pile-reinforced wind turbine foundation was 36% smaller than the existing wind turbine foundation. As a result of the unidirectional cyclic load on a pile-reinforced wind turbine foundation, lateral resistance value was similar to that of the static load in target displacement value, and it showed that the elastic resilience was very large due to pile reinforcement. According to the bending moment measurement of piles embedded in wind turbine foundations and bedrock, bending moments were large in the order of the front row, the right-hand row, and the back row, while the maximum bending moment generation was found on the boundary surface of the wind turbine foundation and the rubble mound layer for the front row, as well as on the boundary surface of the rubble mound layer and bedrock for the right-hand row and back row.

Prediction of rainfall-induced landslide movements in the presence of stabilizing piles

Among the different techniques usually employed to stabilize landslide bodies, the use of one or more rows of piles firmly embedded in the stable portion of the slope is commonly considered a reliable and effective measure. Nevertheless, a landslide may still be reactivated by an increase in the groundwater level due to rainfall. In this context, a novel method is proposed in the present study for a preliminary evaluation of the rainfall-induced movements of landslides in the presence of stabilizing piles. This method uses a water balance equation to evaluate the groundwater level changes due to rainfall, and the motion equation to relate these changes to landslide displacements. The piles contrast the landslide movements by a passive resistance force the value of which depends on the pile–soil failure mode and pile arrangement. The proposed method appears attractive from an engineering viewpoint, since it can be readily implemented in a common electronic sheet and requires few parameters as input data. Most of these parameters can be obtained from conventional geotechnical tests, whereas the remaining ones should be calibrated on the basis of available measurements of rainfall, groundwater level and soil displacement. After performing this parameter calibration, the method may be employed for predictive purposes to relate future landslide movements to expected rainfall scenarios. The predictive capability of the present approach is assessed by comparing the results with those observed in a published case study concerning a landslide body periodically reactivated by rainfall, in which a row of stabilizing piles was installed. • The paper deals with landslides reactivated by rainfall. • A method is proposed for predicting landslide movements in the presence of piles. • The method directly relates rain recordings to landslide movements. • The method is simple and can be readily implemented in a common electronic sheet. • One or more rows of piles are able to reduce the landslide mobility of about 70%.

Behavior Analysis of Traders Regarding Waste Management In The Wonodri Market In Semarang

This research was conducted to describe the behavior of a trader regarding waste management in the Wonodri Market because there are still many traders who do not care about environmental hygiene related to the management of waste produced, such as disposing of trash leftover from the merchandise in an arbitrary manner and indifference from a trader to waste management. Therefore, an analysis of the behavior of traders is needed, one of which is related to independent waste management carried out by market traders. The method used is field survey, observation of market conditions, and literature study. The results showed that the behavior analysis of traders related to waste management in Wonodri Market was still not perfect, it was shown by the presence of piles of garbage in the kiosk/kiosk aisle, and the behavior of traders who still collected garbage mixed with each other in various compositions. This shows that traders care about waste management is still lacking. The level of education and environment of a trader greatly influences the knowledge and perceptions of traders in waste management in the Wonodri Market. The behavior of traders greatly influences the maintenance of a clean, comfortable and safe market environment, so that it does not hinder the buying and selling process between sellers and buyers and does not break the economic chain that occurs.

Study of the Force and Deformation Characteristics of Subsea Mudmat-Pile Hybrid Foundations

Abstract To study the force and deformation characteristics of subsea mudmat-pile hybrid foundations under different combined loads, a project at a water depth of 200 m in the South China Sea was studied. A numerical model of a subsea mudmatpile hybrid foundation is developed using the numerical simulation software FLAC3D. The settlement of the seabed soil, the bending moments of the mudmat, and the displacements and bending moments along the pile shaft under different load combinations, including vertical load and horizontal load, vertical load and bending moment, and horizontal load and bending moment load, are analyzed. The results indicate that settlement of the seabed soil is reduced by the presence of piles. The settlement of the mudmat is reduced by the presence of piles. Different degrees of inclination occur along the pile shaft. The angle of inclination of pile No. 1 is greater than that of pile No. 2. The dip directions of piles No. 1 and No. 2 are identical under the vertical load and bending moment and are opposite to those under the other combined loads. The piles that are located at the junctions between the mudmat and the tops of the piles are easily destroyed.

Lateral spreading near deep foundations and influence of soil permeability

A three-dimensional finite element (FE) model is calibrated based on a large-scale (1g) shake-table experiment. In this experiment, single piles were subjected to liquefaction-induced lateral spreading. The testing configuration, experimental results, and FE framework are presented and discussed. The presence of piles in this fully saturated ground model caused a significant reduction in the extent of accumulated lateral soil deformation. In this regard, high shear strains, additional to those in the free field, occur as the soil moves around the piles in the downslope direction. The associated shear-induced tendency for dilation increases the effective confinement, and reduces the resulting downslope deformations. As such, an FE parametric study is undertaken to investigate the effect of soil permeability on this observed liquefaction-induced lateral response. As the prescribed soil permeability increased (in the silt–sand range), higher levels of ground lateral deformation occured, albeit with a lower pile head displacement and lateral load. Eventually, high permeability (in the gravels range) precluded the accumulation of significant excess pore pressure, with low levels of both soil and pile lateral displacement. On this basis, permeability is highlighted as a critical potentially primary parameter in dictating the effects of liquefaction-induced lateral load on embedded foundation systems.

Limit analysis approach for accessing stability of three-dimensional (3-D) slopes reinforced with piles

ABSTRACTThe stabilization of slopes by placing piles is one of the most innovative and effective slope reinforcement techniques in the coastal engineering in recent years. Due to the simplicity and efficiency, limit analysis method is the most common approach for assessing the stability of slopes. However, the majority of existing limit analysis methods is limited to slope without the presence of piles. In this technical note, a novel upper-bound limit analysis method was proposed to access the stability of three-dimensional slopes reinforced with piles incorporating the admissible rotational failure mechanism where toe failure, face failure, and base failure were taken into account. The effects of key designing parameters, e.g., pile location, pile spacing, slope angle, slope width on the stability of earth slopes, and geometry of critical slip surface were presented and discussed. The results demonstrate that the proposed approach is more appropriate for assessing the stability of slopes reinforced with piles and can be also utilized in the design of piles stabilizing the unstable slopes.

The Rotational Model: A New Hypothesis for Thylakoid Stacking

The most enigmatic feature of mature thylakoids of Angiosperms is the presence of piles of membranous discs forming the cylindrical structures known as grana. Although some models aim to elucidate their formation, until now the mechanism governing the architecture of thylakoid stacks remains obscure. In this work a new model is presented aiming to explain the way thylakoids stack. In comparison with previous models, this model proposes a dynamic mechanism for the rapid selfassembly of thylakoid stacks and their subsequent disassembly under the influence of a variety of physicochemical factors and is consistent with the evolutionary origin of these membranes and their ontogenetic continuity. The model proposes that, under the influence of attractive electrostatic forces, the membranes come closer in a parallel alignment and the photosystem II/light harvesting complexes migrate laterally forming circular aggregates. Finally the thylakoids rotate around the vertical axis of the superimposed aggregates, under the action of a torque.

Base stability of multi-propped excavations in soft clay subjected to hydraulic uplift

Excavations in soft clay underlain with an aquifer may be destabilized by hydraulic uplift. Previous studies on this subject are based mainly on field observations. Dewatering from the aquifer is a common method to improve base stability where ground settlement is not a major concern. Alternatively, piles readily installed as part of the top-down construction method for multi-propped excavation may be considered to provide base stability and minimize ground settlement outside the excavation. This paper presents results from two centrifuge tests that were conducted to simulate multi-propped excavations in-flight (with and without piles) in soft clay destabilized by hydraulic pressure from an underlying sand aquifer. Moreover, coupled three-dimensional finite element analyses were carried out to back-analyse the centrifuge tests. Numerical parametric studies were also conducted to study the influence of pile length on the effectiveness of base stabilization. It is revealed that both for excavations with and without piles, the artesian pressure required to initiate uplift inside the excavation is about 1.2 times the overburden pressure of the clay. By using “anti-uplift” piles inside the excavation, the ultimate hydraulic uplift resistance increases by 16%, while the uplift movement can be reduced by 80%. The presence of piles also increases the passive resistance in front of the wall by 70%, but reduces the mobilized undrained shear strength, cu, of clay by 53%.

The Influence of Engineering Pile on the Bottom Upheaval of Foundation Pit

In foundation pit engineering, the presence of pile plays an important role on the pit stability and deformation control. The bottom upheaval of deep foundation pit is a key criterion of judging the foundation stability and deformation. This paper built the 3D finite element model to analyze the influence of different factors (pile diameter, pile length and pile spacing) on the bottom upheaval, and concluded that: when pile length and pile spacing is constant, changing the pile diameter can hardly affect the bottom upheaval; as the pile length increased, the inhibitory effect to the bottom upheaval grew stronger with a gradually decreased growth rate; increasing pile spacing can significantly reduce the bottom upheaval, and the smaller the pile spacing, the smaller the upheaval. The concept of upheaval inhibition rate was defined to evaluate the influence of different factors of pile layout on the bottom upheaval. A correction method of calculating the bottom upheaval of foundation pit with engineering pile was proposed. An engineering instance of Shanghai Natural History Museum foundation pit was studied, and the result showed that the bottom upheaval calculated by the correction method is less than the upheaval calculated by method of residual stress, which was more close to the monitoring data. The influence of engineering pile on bottom upheaval of foundation pit should not be neglected where a large number of piles were present in deep foundation pit.

Solid Waste Management in Bangladesh

Bangladesh was known as the 'Greanest Country' of World due to its natures and overwhelming presence of green trees and hilly areas. But now due to the presence of piles of refuses dotting and improper waste management, the clean lines of the city has been facing acute degradation. The study aims at exploring the present scenario of solid waste management in Bangladesh. This paper highlights the status of waste generation and its management, obstacles to proper waste management. Finally it suggests some guidelines in the way of proper waste management.

Snow heterogeneity in Luleå, Sweden

Snow water equivalent (SWE) and snow covered area (SCA) are fundamental considerations when planning for snowmelt events. Depth, density and albedo measurements are used to demonstrate the spatial variability of SWE in the city of Luleå, Sweden. Undisturbed urban snow is similar to nearby rural snow (albedo 0.5–0.6, density 200–300 kg m−3) whereas ploughed snow piles have a wide range of characteristics (albedo<0.3–0.5, density 250–700 kg m−3). Snow piles are located on permeable surfaces in suburbs and impervious surfaces where landuse is intense. Snowmelt runoff simulated assuming first a homogenous then a heterogeneous snowpack shows that the presence of piles can reduce the maximum volume of melt and extend the melt period.