• Title/Summary/Keyword: Foundation model

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A foundation treatment optimization approach study in hydraulic engineering

  • Zhang, Tianye;Liu, Shixia
    • Earthquakes and Structures
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    • v.15 no.2
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    • pp.215-225
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    • 2018
  • To reach a better foundation treatment project, an optimized analysis of composite foundation was studied in the field of hydraulic engineering. Its unique characteristics in hydraulic engineering were concluded. And, the overall and detailed analysis of the composite foundation model established was carried out. The index parameters of the vertical reinforced rigid pile composite foundation were formulated. Further, considering the unique role of cushion in hydraulic engineering, its penetration and regularity were analyzed. Then, comparative and optimized analyses of cushion multistage physical dimensions and multistage material characteristics were established. The parameters of the piles distance were optimized and the multilevel scientific and reasonable parameters information was obtained. Based on the information of these parameters, the practical application was verified. It effectively supported the effective application of vertical reinforcement rigid pile composite foundation in hydraulic engineering. The service mechanism of composite foundation was fully analyzed.

Factors Related to Treatment Refusal in Taiwanese Cancer Patients

  • Chiang, Ting-Yu;Wang, Chao-Hui;Lin, Yu-Fen;Chou, Shu-Lan;Wang, Ching-Ting;Juang, Hsiao-Ting;Lin, Yung-Chang;Lin, Mei-Hsiang
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.8
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    • pp.3153-3157
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    • 2015
  • Background: Incidence and mortality rates for cancer have increased dramatically in the recent 30 years in Taiwan. However, not all patients receive treatment. Treatment refusal might impair patient survival and life quality. In order to improve this situation, we proposed this study to evaluate factors that are related to refusal of treatment in cancer patients via a cancer case manager system. Materials and Methods: This study analysed data from a case management system during the period from 2010 to 2012 at a medical center in Northern Taiwan. We enrolled a total of 14,974 patients who were diagnosed with cancer. Using the PRECEDE Model as a framework, we conducted logistic regression analysis to identify independent variables that are significantly associated with refusal of therapy in cancer patients. A multivariate logistic regression model was also applied to estimate adjusted the odds ratios (ORs) with 95% confidence intervals (95%CI). Results: A total of 253 patients (1.69%) refused treatment. The multivariate logistic regression result showed that the high risk factors for refusal of treatment in cancer patient included: concerns about adverse effects (p<0.001), poor performance(p<0.001), changes in medical condition (p<0.001), timing of case manager contact (p=.026), the methods by which case manager contact patients (p<0.001) and the frequency that case managers contact patients (${\geq}10times$) (p=0.016). Conclusions: Cancer patients who refuse treatment have poor survival. The present study provides evidence of factors that are related to refusal of therapy and might be helpful for further application and improvement of cancer care.

Model Test and Deformation Analysis of the Improved Soft Foundation(I) (개량연약지반의 모형실험과 변형해석(I))

  • 이문수;이진수;오재화
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.36 no.2
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    • pp.67-78
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    • 1994
  • This is a fundamental study aiming at scrutinizing the effect of reinforcement and deformation characteristics of soft clayey foundation improved by vanous technical treatments. Among many methods proposed thus far, geotextile was selected for the purpose of improvement of the model soil foundation on which plate loading test was subsequently performed. Loading test has been carried out with the variation of the location and number of covering layers of geotextile, and actual values for ground deformation and geotextile effect were secured. As for technique on deformation analysis, elasto-plastic model for soil, elastic model for sand, and beam theory for geotextile were coupled with satisfactory results between observed and numerical values.

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Physical modelling of sliding failure of concrete gravity dam under overloading condition

  • Zhu, Hong-Hu;Yin, Jian-Hua;Dong, Jian-Hua;Zhang, Lin
    • Geomechanics and Engineering
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    • v.2 no.2
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    • pp.89-106
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    • 2010
  • Sliding within the dam foundation is one of the key failure modes of a gravity dam. A two-dimensional (2-D) physical model test has been conducted to study the sliding failure of a concrete gravity dam under overloading conditions. This model dam was instrumented with strain rosettes, linear variable displacement transformers (LVDTs), and embedded fiber Bragg grating (FBG) sensing bars. The surface and internal displacements of the dam structure and the strain distributions on the dam body were measured with high accuracy. The setup of the model with instrumentation is described and the monitoring data are presented and analyzed in this paper. The deformation process and failure mechanism of dam sliding within the rock foundation are investigated based on the test results. It is found that the horizontal displacements at the toe and heel indicate the dam stability condition. During overloading, the cracking zone in the foundation can be simplified as a triangle with gradually increased height and vertex angle.

Numerical Simulation of Soil-Structure Interaction in Centrifuge Shaking Table System (지반-구조물 상호작용 원심모형시험에 대한 수치해석)

  • Kim, Dong-Kwan;Park, Hong-Gun;Kim, Dong-Soo;Lee, Sei-Hyun
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.09a
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    • pp.201-204
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    • 2010
  • Earthquake load to design a structure has been calculated from a fixed base SDOF model using amplified surface accelerations along soft soil layers. But the method dose not consider a soil-structure interaction. Centrifugal experiments that were consisted of soil, a shallow foundation and a structure were performed to find the effects of soil-structure interaction. The experiments showed that mass and stiffness of the foundation affected a response of the structure and nonlinear behavior of soil near the foundation. And a rocking displacement caused by overturning moment affected the response and increases a damping effect. In this study, the centrifugal experiment was simulated as a two dimensional finite element model. The finite element model was used for nonlinear time domain analysis of the OpenSees program. The numerical model accurately evaluated the behaviors of soil and the foundation, but the rocking effect and the behavior of structure were not described.

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A mathematical model to recover missing monitoring data of foundation pit

  • Liu, Jiangang;Zhou, Dongdong;Liu, Kewen
    • Geomechanics and Engineering
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    • v.9 no.3
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    • pp.275-286
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    • 2015
  • A new method is presented to recover missing deformation data of lateral walls of foundation pit when the monitoring is interrupted; the method is called Dynamic Mathematical Model - Parameter Interpolation. The deformation of lateral walls of foundation pit is mainly affected by the type of supporting structure and the situation of constraints, therefore, this paper mainly studies the two different kinds of variation law of deep horizontal displacement when the lateral walls are constrained or not, proposes two dynamic curve models of normal distribution type and logarithmic type, deals with model parameters by interpolating and obtains the parameters of missing data, then missing monitoring data could be Figured out by these parameters. Compared with the result from the common average method which is used to recover missing data, in the upper 2/3 of the inclinometer tube, the result by using this method is closer to the actual monitoring data, in the lower 1/3 part of the inclinometer tube, the result from the common average method is closer to the actual monitoring data.

Free Vibrations of Thick Plates with Concentrated Masses on In-homogeneous Pasternak Foundation (비균질 Pasternak지반 위에 놓인 집중질량을 갖는 후판의 자유진동)

  • 이용수;이병구;김일중;이태은
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.13 no.4
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    • pp.281-289
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    • 2003
  • Recently, as high-rise buildings increase steeply, sub-structures of them are often supported on in-homogeneous foundation. And there are many machines in sub-structures of buildings, and slabs of sub-structures are affected by vibration which they make. This paper deals with vibration of plates with concentrated masses on in-homogeneous foundation. Machines on plates are considered as concentrated masses. In-homogeneous foundation is considered as assigning $k_{w1}$ and $k_{w2}$ to Winkler foundation parameters of central region and side region of plate respectively, and foundation is idealized to use Pasternak foundation model which considered both of Winkler foundation parameter and shear foundation parameter. In this paper, applying Winkler foundation parameters which $k_{w1}$and $k_{w2}$ are 10, $10^2$, $10^3$ and shear foundation parameter which are 10, 20 respectively, first natural frequencies of thick plates with concentrated masses on in-homogeneous foundations are calculated.

Numerical Analysis for High-rise Building Foundation and Further Investigations on Piled Raft Design

  • Won, Jinoh;Lee, Jin Hyung;Cho, Chunwhan
    • International Journal of High-Rise Buildings
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    • v.4 no.4
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    • pp.271-281
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    • 2015
  • This paper introduces detailed three-dimensional numerical analyses on a bored pile foundation for a high-rise building. A static load test was performed on a test pile and a numerical model of a single pile, which was calibrated by comparing it with the test result. The detailed numerical analysis was then conducted on the entire high-rise building foundation. Further study focused on soil pressures under the base slab of a piled raft foundation. Total seven cases with different pile numbers and raft-soil contact conditions were investigated. The design criteria of a foundation, especially settlement requirement were satisfied even for the cases with fewer piles under considerable soil pressure beneath the base slab. The bending moment for the structural design of the base slab was reduced by incorporating soil pressures beneath the base slab along with bored piles. Through the comparative studies, it was found that a more efficient design can be achieved by considering the soil pressure beneath the slab.

Stochastic dynamic instability response of piezoelectric functionally graded beams supported by elastic foundation

  • Shegokara, Niranjan L.;Lal, Achchhe
    • Advances in aircraft and spacecraft science
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    • v.3 no.4
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    • pp.471-502
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    • 2016
  • This paper presents the dynamic instability analysis of un-damped elastically supported piezoelectric functionally graded (FG) beams subjected to in-plane static and dynamic periodic thermomechanical loadings with uncertain system properties. The elastic foundation model is assumed as one parameter Pasternak foundation with Winkler cubic nonlinearity. The piezoelectric FG beam is subjected to non-uniform temperature distribution with temperature dependent material properties. The Young's modulus and Poison's ratio of ceramic, metal and piezoelectric, density of respective ceramic and metal, volume fraction exponent and foundation parameters are taken as uncertain system properties. The basic nonlinear formulation of the beam is based on higher order shear deformation theory (HSDT) with von-Karman strain kinematics. The governing deterministic static and dynamic random instability equation and regions is solved by Bolotin's approach with Newmark's time integration method combined with first order perturbation technique (FOPT). Typical numerical results in terms of the mean and standard deviation of dynamic instability analysis are presented to examine the effect of slenderness ratios, volume fraction exponents, foundation parameters, amplitude ratios, temperature increments and position of piezoelectric layers by changing the random system properties. The correctness of the present stochastic model is examined by comparing the results with direct Monte Caro simulation (MCS).

A Study on the Behavior of Soft Clay Foundation Reinforced with Soil Cement Piles by Centrifugal Model Tests (원심모형실험에 의한 시멘트 개량말뚝으로 보강된 연약점토지반의 거동에 관한 연구)

  • Lee, Cheo-Keun;Shin, Bang-Woong;Heo, Yol;Ahn, Sang-Ro
    • Geotechnical Engineering
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    • v.10 no.2
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    • pp.109-120
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    • 1994
  • One of problems being faced during construction of soil structures along the coastal regions is the stabilization of soft clay foundation, In this study, centrifugal model bests were conducted to investigate behavior effect of soft foundation reinforced by cement -soil piles for the stabilization of softs clay foundation during the embankment construction. This paper presents results of settlement and heaving behavior of reinforced and unreinforced foundation with time under the swaged loading for different best conditions. The test results have shown that the reductions of vertical settlement of the foundation and heaving of the ground surface adjacent to the embankment are greatly influenced by strength of improved pile, and moisture content, and especially the ratio of replacement area.

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