Deformation Of Pile Foundation Research Articles

Resarch on Calculation Method of Pile Horizontal Response under Combined Loads

The main function of the pile foundation is to bear the vertical load, but in actual engineering, the pile foundation usually bears combined loads which contain vertical load, lateral load and bending moment. Under combined loads, due to the P-Δ effect, the calculation of the bearing capacity and deformation of the pile foundation is very complicated. The small deformation superposition principle recommended by the current pile foundation codes fails to consider the resistance of the soil around the pile under the combined loads, and it is difficult to accurately evaluate the influence of P-Δ effect on the bearing capacity and deformation of pile foundation. In view of this, this paper firstly starts from the potential energy equation of the pile-soil system and deduces the calculation formula for the horizontal displacement of the pile considering the P-Δ effect, and it is verified in conjunction with related calculation examples. Then the factors affecting the P-Δ effect are discussed in detail, and the results show that the larger the load ratio is, the more obvious the P-Δ effect will be; when the pile top is fixed under the same load condition, the P-Δ effect will be significantly weakened.

Study on Settlement and Deformation of Urban Viaduct Caused by Subway Station Construction under Complicated Conditions

With the rapid development of urbanization, the speed of constructing urban underground space and ground foundation engineering is accelerated. With the shortage of land resources, the distance between underground engineering and surface engineering is getting closer and closer, and the contradictions and problems between projects are becoming more and more serious. Based on the new subway station, this paper passes the existing urban viaduct in a short distance. The settlement and deformation of pile foundation and buildings caused by the excavation of the subway station is studied by using ROCSCIENCE software and site monitoring method. The potential risk sources around the station are pile foundations 18.5 m away, residential buildings 15 m away, storm water pipes 7.3 m away, and high‐pressure gas pipes at 5.6 m. According to the construction requirements of pile foundation settlement deformation during metro station excavation, we set up construction standards. The settlement of the buildings and pipelines around the metro station should not exceed 3 mm, and the horizontal displacement should not exceed 2 mm. The diaphragm wall is adopted to surround the subway station, and the ground is reinforced by advanced grouting. The results show that, during the excavation of the foundation pit of the metro station, the ground and the building will have obvious settlement deformation and the depth of deformation can reach 9 mm, which is more than the allowable value. The settlement deformation of the ground and the surrounding buildings can be controlled within 3 mm by strengthening the foundation pit support and ground advance‐grouting reinforcement. The control of construction deformation can meet the construction requirements.

Analysis of influence of subway station deep foundation pit excavation on adjacent bridge piles

Based on the engineering background of the deep foundation pit construction of Shenyang metro Line 10, the numerical simulation software Midas the GTS NX, and the three-dimensional integral calculation model considering the interaction of foundation pit supporting structure, surrounding soil and viaduct is established, and the numerical simulation value and the measured data are compared and analyzed, the applicability of the model is verified, the influence of foundation pit excavation on the deformation of pile foundation is studied, and the optimization scheme is given. The construction plan of Simulation + forecast is established to guide the practical construction of the project. The results show that when the depth of the pile foundation is 1.5 times the depth of the foundation pit, and the horizontal displacement of the pile foundation is within 1/2 of the control value, this is the optimal depth of the pile foundation. This is the minimum standard safe distance when the pier is 1/2 from the depth of the foundation pit.

Analysis and Evaluation of the Deformation of Pile Foundation Next to Filling under the Soft Ground Pre-Treatment of Rigid Long-Short Pile

Analysis and Evaluation of the Deformation of Pile Foundation Next to Filling under the Soft Ground Pre-Treatment of Rigid Long-Short Pile

Application of distributed optical fiber sensing technique in pile foundation monitoring

Compared with traditional point monitoring technique, distributed optical fiber sensing technique, with the advantages of long transmission distance, good durability, high precision and continuous monitoring, has been used widely in slope, tunnel and pile foundation engineering et al. Based on a bridge pile foundation project, the distributed optical fiber was used to monitor the stress and deformation of pile foundation during the construction process. Through comparing the results with traditional point monitoring technique, it shows that the distributed optical fiber sensing technique is of high accuracy and with good consistent with the traditional monitoring technique.

Structural Analysis of Frame-Type Levee Using P-Y Curve Method

Frame-type levee is common type of levee in southern China. The deformation of pile foundation of frame-type levee is affected greatly by the river level. Large deformation is its notable feature. Taking levee project located in Wuzhou city of Guangxi province of China as research background, “P-Y curve” method is used to analyze the deformation and internal force of pile foundation of frame-type levees under the different working conditions. The results show that the maximum deformation of pile foundation reaches 0.18m, which imply the pile foundation is not safe under the condition of high river lever during flood season. Furthermore, the results show that “P-Y curve” method is feasible for simulating the pile with large deformation. It overcomes shortcomings of traditional methods such as “K” method or “M” method, which are not applicable to simulating pile with large deformation.

Probabilistic Seismic Design of Pile Foundations in Non Liquefiable Soil by Response Spectrum Approach

The behavior of pile foundations in non liquefiable soil under seismic loading is considerably influenced by the variability in the soil and seismic design parameters. Hence, probabilistic models for the assessment of seismic pile design are necessary. Deformation of pile foundation in non liquefiable soil is dominated by inertial force from superstructure. The present study considers a pseudo-static approach based on code specified design response spectra. The response of the pile is determined by equivalent cantilever approach. The soil medium is modeled as a one-dimensional random field along the depth. The variability associated with undrained shear strength, design response spectrum ordinate, and superstructure mass is taken into consideration. Monte Carlo simulation technique is adopted to determine the probability of failure and reliability indices based on pile failure modes, namely exceedance of lateral displacement limit and moment capacity. A reliability-based design approach for the free head pile under seismic force is suggested that enables a rational choice of pile design parameters.

杭と架構を一体とした弾性解析による杭基礎の水平力作用時の応力-変形系(一層地盤の場合)

Up to the present, the lateral stress of pile foundations have been usually designed without superstructure so, from the strict theoretical point of view, the stress and deformation are not considered to be correct. This paper expressed the systematic theory of pile foundation with superstructure by elastic analysis on single layer ground under lateral load. 1. General characteristics of pile foundation are explained not by absolute value but by stress per unit deformation. 2. General characteristics are controlled by non dimensional rotation. θo/(yoβ) or θo/(yoη). 3. Non dimensional rotation is related with ω:the restraint factor of rotation. ω:consists of EcKg(kNm):rigidity of ground beam, E_pI_p(kNm^2):bending rigidity of pile and β or η constant of ground character sties. 4. The stress and deformation of pile foundation are able to be easily calculated using the results of this paper.