Table of Content

    29 January 2016, Volume 50 Issue 01 Previous Issue    Next Issue
    Determination of Soil Parameters for Numerical Simulation of an Excavation
    ZHAO Xiangshan, CHEN Jinjian, HUANG Zhonghui, WANG Jianhua
    2016, 50 (01):  1-7.  doi: 10.16183/j.cnki.jsjtu.2016.01.001
    Abstract ( 1076 )   HTML ( 297 )   PDF (1064KB) ( 487 )   Save

    It is relatively difficlut to determine the parameters adopted in numerical simulation of excavation due to the non-uniformity and uncertainties of soil. In this paper, an inverse analysis method for deep excavation based on the Pareto multiobjective optimization was proposed. The excavation process was first simulated in ABAQUS. A multialgorithm genetically adaptive multiobjective method (AMALGAM) was then invoked by Matlab to identify the soil parameters in excavation with multiple types of field observations. The proposed method was applied to the analysis of a well-instrumented deep well to predict the wall deflection, as well as the ground surface settlement in following excavation with acceptable accuracy. In addition, the nine soil parameters obtained from the inverse analysis on Changshou Road Station excavation were presented, which probably could be uesd as reference for other excavations.

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    Modelling of Saturated Soil Dynamic Coupled Consolidation Problems Using Three-Dimensional Scaled Boundary Finite Element Method
    XU Bin, XU Manqing, WANG Jianhua
    2016, 50 (01):  8-16.  doi: 10.16183/j.cnki.jsjtu.2016.01.002
    Abstract ( 1093 )   HTML ( 18 )   PDF (744KB) ( 356 )   Save

    Based on the Biot's dynamic coupled consolidation theory, the scaled boundary finite-element method was developed to correctly model the dynamic unbounded far-field boundary of three-dimensional (3D) fully saturated soil in this paper. Body forces and surface tractions were considered in the derivation. The concept of similarity, the compatibility equation, Biot's coupled consolidation equations, and the Galerkin's weighted-residual method were used to derive the formulation for the governing equations. The main difference from the single-phase version was the presence of pore water pressures as additional parameters to be solved, in addition to the displacements, strain and stress which were incorporated into the static-stiffness matrices by producing fully coupled matrices. Solving the resulting equations yielded a boundary condition satisfying the far-field radiation condition exactly. The computed solutions were exact in a radial direction (perpendicular to the boundary and pointing towards infinity), while converging to the exact solution in the finite element sense in the circumferential direction parallel to the soil-structure boundary interface.

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    Determining Methods for Soil Parameters Based on Field Measurements in Tunnel Engineering
    REN Ying-nan, CHEN Jinjian, HUANG Zhonghui, WANG Jianhua
    2016, 50 (01):  17-21,29.  doi: 10.16183/j.cnki.jsjtu.2016.01.003
    Abstract ( 433 )   HTML ( 170 )   PDF (1000KB) ( 246 )   Save

    In this paper, an efficient multi-objective back-analysis method of tunnel engineering was proposed by using the AMALGAM as the genetic algorithm, and by using the Pareto optimal theory as the evaluation criterion. The proposed method was applied to a test section of the West Changjiang Road tunnel project. Taking horizontal displacement as one objective, and ground settlement as the other, the soil parameters of the key layers were estimated using this method. The optimal solution was compared with the measured results, which proved that the multi-objective back analysis was superior to the single-objective back analysis in accuracy. Meanwhile, predictive analysis was taken based on the results of back analysis, and was verified as feasible. This method can provide references for environmental impact analysis of tunnel engineering.

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    Optimization of BuiltonStilts Type DiscShapeLike Spatial Structures
    HONG Ronghua, WANG Xun, ZHOU Dai, LI Fangfei, CHEN Yian
    2016, 50 (01):  21-29. 
    Abstract ( 894 )   Save
    Numerical Simulation of Wind Field and WindResistant Shape Abstract: Based on the computational fluid dynamics (CFD) method, the wind flow characteristics and wind pressure distribution of the builtonstilts type discshapelike spatial structure were numerically simulated at different incoming wind directions by using the Fluent software. The influence of the height of the supporting column, the heightspan ratio of the top and the bottom structural surfaces on wind pressure distribution and windloading shape coefficients was analyzed. The results show that the height of the supporting column should be chosen carefully to allow wind pass easily and to reduce wind load force. With the increase of heightspan ratio of the top and the bottom structural surfaces, the positive wind pressure on windward, the vortex effect on the leeward and the overall wind loading force increase significantly. It is found out that a lower curvature surface will significantly improve the structural windresistant characteristics. Finally, some conclusions on windresistant structural shape optimization were reached, which could provide some references for the design of this kind of structures.
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    Analysis of PostBreakage Strength of Laminated Glass
    JI Qing, YANG Jian, ZHOU Dai
    2016, 50 (01):  30-34. 
    Abstract ( 1035 )   Save
    Abstract: In this paper, a novel method to determine the postbreakage strength of laminated glass was proposed based on the three stage model by incorporating the yield line theory. The influences of different design parameters on the post breakage strength of laminated glass were analyzed using the proposed method. The results show that the glass thickness, supporting conditions, interlayer thickness, length of glass plate have a great influence on the post breakage strength of laminated glass.
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    Estimation of Cutting Force of Rock Cutting with Conical Picks
    OUYANG Yiping, YANG Qi
    2016, 50 (01):  35-40. 
    Abstract ( 867 )   Save
    Abstract: A method or formula that can accurately estimate the peak cutting force of rock cutting with conical picks is quite valuable. In this paper, formulas with a simple form and wide application and low error were created by analyzing the existing formulas and experimental data, and the relationships between peak cutting force and rock properties and the cutting depth were clarified. The peak cutting force and cutting depth follow a power law with an exponent between 1.1 and 1.5. The uniaxial compressive stress is the most important rock properties affecting the peak cutting force. The formula created in this paper was proved by experiments to be more accurate in estimating peak cutting forces compared to those existing formulas.
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    Stress Model of ConcreteFilled Rectangular Fiber Reinforced Polymer Tubes Under Axial Compression
    LIANG Benliang
    2016, 50 (01):  41-46. 
    Abstract ( 648 )   Save
    Abstract: Based on the TsaiWu yield criterion, the stress analysis of fiber reinforced polymer (FRP) tubes was conducted. And the twin shear unified strength theory was used to analyze the stress of the core concrete under triaxial stress state. Besides, the strength calculation method to predict the ultimate stress under axial compression of short concrete columns with rectangular crosssection confined by FRP tubes was deduced to provide an effective method and the reference for the calculation of the ultimate bearing capacity.
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    Simulation Study of Thermal and Moisture Transfer of DoubleShell MicroNano Capsules Based on Interface Molecular Dynamics
    SHANG Jianli,XIONG Lei,ZHANG Hao
    2016, 50 (01):  47-51. 
    Abstract ( 777 )   Save
    Abstract: To further study the effect of building gypsum added with doubleshell micronanocapsules with phase changing materials on heat and moisture transfer in porous walls, a model of the coupled heat and moisture in porous material with phase changing micronanocapsules was proposed. The thermal parameters of capsule interface were given by using pair potential and multibody potential of interface molecular dynamics, and by taking into account the feature of phase changing micronancapsules from the outside to the inside in phase transition. Meanwhile, the hydrophilic nature of outside shell and the effect of gypsum porporsit on the coupled heat and moisture by water adsorbed/desorbed were considered, and the moisture parameter model of capsule interface was proposed. And computer software was utilized to solve the equation of the added or nonadded material to deal with the simulation and measured data. The results show that the model can be used to simulate the heat and moisture transfer process in porous wall with phase change capsules. Key words:
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    A Direct Approach to Skeletal Structures Statics and Dynamics
    ZHOU Juna,RAO Zhushib,TA Naa
    2016, 50 (01):  52-58. 
    Abstract ( 818 )   Save
    Abstract: The precision of finite element method is restricted by mesh density. To solve this problem, an analytical method for arbitrary complex bar system was proposed based on the nodal method. The nodal compatibility equation of displacement and the equilibrium equation of internal force were considered. The spectral coefficients were treated as the unknowns. The deformation and internal section force were described by the exact solutions of corresponding problems. The process of the construction of the coefficient matrix of the equation of the system was illustrated in an algebraic symbolic way, providing basis for general program development. Two special modelling procedures, distributed load and hinge joint, were investigated and given. A plane steel frame buckling analysis and a space pipe line harmonic analysis were launched. The results confirm that the present method is highly precise and requires a small number of elements. The method is well suited for the requirement of analytical solutions.
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    Equivalent Static Wind Load of a LongSpan Truss String Structure
    QIAO Shuaibin1,WANG Xun1,WANG Zitong1,ZHOU Dai1,2
    2016, 50 (01):  59-64. 
    Abstract ( 813 )   Save
    Abstract: The timehistory of wind velocity was simulated by using the harmonic superposition method, which was then turned into pressure timehistory of wind. By using the ANSYS software, the FEM model for the structural system was constructed, and the structural windinduced vibration responses under different incoming winds were calculated by using the simulated wind pressure timehistory. Moreover, a novel equivalent static wind load was established, where the windinduced dynamic amplification factor was combined with the instantaneous wind pressure distribution at a specific time. Finally, from numerical examples, the equivalent static wind load distribution based on the minimum vertical reaction forces and the maximum nodal displacement of the truss were obtained. Key words: longspan truss string structure; wind velocity simulation; windinduced dynamic
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    Distribution of Wind Load on Purlins of Open Metal Roofs at the Airport
    AI Huilin1,ZHOU Zhiyong2
    2016, 50 (01):  65-71. 
    Abstract ( 932 )   Save
    Abstract: It is not easy to directly test the wind loads on small components using wind tunnel test of scale model. Therefore, the technology of numerical wind tunnel was used. By the establishment of the building and the space model of its roof purlins, and by dividing local grid refinement, the wind load distribution on the purlins of open roofs was obtained at different wind angles. The results show that when subjected to skew wind, the open purlins are more unfavorable, and the horizontal shear force is more significant than the vertical suction, which is an important part of wind load calculation. The wind load distribution on the purlins has obvious regularity. First, in the cusp region of the roof, the wind load is the largest since the roof curvature is the maximum, and the air flow produces a strong separation of convection to form a strong vertical suction and horizontal shear wind force. Second, in the outer area of the roof, the wind load is large too, which is directly related to the air separation from the architecture marginal zone. Finally, in the inner area of the roof, the wind load is significantly smaller and more uniform. By closing the bottom of the purlin, the extreme wind load on the outer area of the roof can be effectively reduced by more than 20%, but it does not have obvious effect on the inner area of the roof. It is recommended that the initial design, the bottom of the purlin should be closed only at the edge of the roof.
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    Experimental Study of Uniaxial Tensile Mechanical Properties of Fluorinated Ethylene Propylene Foils
    LI Chun,CHEN Wujun,HE Shizan
    2016, 50 (01):  72-77. 
    Abstract ( 643 )   Save
    Abstract: A series of uniaxial mechanical property tests were conducted for the FEP foils(thickness:150 μm)and the specimens were cut from foils along the machine direction(MD). The transverse direction(TD). The yield strength, the tensile strength and the elongation at break were obtained from the uniaxial tensile tests by using four kinds of tensile speed. The linear fitting formulas through using the tensile strain rate. The variable were proposed. The analysis of the secant modulus and the residual strain per cycle were obtained via the uniaxial cyclic tensile tests by using three values of cycle stress. The analysis of creep development was conducted from the results of the creep tests by using three kinds of stresses. The results show that the yield strength, the tensile strength, the elongation at break of the FEP foils material are increased with the increase of tensile strain rate. The secant modulus and the residual strain remain stable with the increase of cyclic times. The large creep is observed in the stress of 9 MPa. The result of the tests can provide valuable reference for practical membrane engineering design of FEP foils.
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    Mechanical Property Test at Different Unloading Velocities of Metamorphic Quartz Sandstone
    GUO Xifeng1,2,YIN Jianmin1,YAN Echuan2,ZHANG Lijie1,2
    2016, 50 (01):  78-83. 
    Abstract ( 837 )   Save
    Abstract: To study rock mechanical characteristics at different unloading velocities, taking the metamorphic quartz sandstone from Dabenliugou quarry special high slope in Jinping Hydropower Station as an example, unloading tests at different unloading velocities and confining pressures were conducted. Based on the tests, relationship curves between stress and strain were obtained, and affection laws of unloading velocity on stress and strain relationship, failure properties, failure stress difference, strength parameters were mainly studied. The results show that the brittle feature of unloading effect on rock failure is more obvious. The specimens under conventional loading test are compression shear failure, while the unloading specimens are tension shear failure. Elastic modulus is decreased with confining. As Vu becomes faster, the nonlinearity become more obvious, while the Poisson ratio is increased slowly. The rock cohesion is reduced but the inner friction angle is increased under unloading condition.
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    Numerical Simulation of Rock Cutting in 3D with SPH Method and Estimation of Cutting Force
    OUYANG Yiping,YANG Qi
    2016, 50 (01):  84-90. 
    Abstract ( 872 )   Save
    Abstract: The effects of cutting parameters and rock properties on cutting forces were studied through 3D simulation of rock cutting in the LSDYNA with the MohrCoulomb model as rock material model and the SPH method. A formula to estimate cutting forces was created based on the relationships between cutting forces and cutting parameters, as well as rock properties drawn from the simulation results. The calculating results of the proposed formula were compared with the experiments. The simulation results show that cutting depth, rake angle, cutting width, cohesion and internal friction angle of rock have significant effects on cutting forces and that the variation of cutting speed have a small effect when the speed is slow. The interaction between the cutter tooth and rock particles beside it was taken into consideration in the 3D simulation of rock cutting. It made the simulation agree better with the experiments than the 2D cutting model. The formula created in this paper can estimate the tangential cutting forces of the simulation with less errors and its calculating results agree well with the experimental results. The SPH method is proved to be a reliable method in rock cutting with cutter tooth.
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    Influence of HullWaterjet Interaction on Propulsion Performances of Waterjet
    LIU Chengjiang1,WANG Yongsheng1,GU Chengzhong2
    2016, 50 (01):  91-97. 
    Abstract ( 972 )   Save
    Abstract: The computational fluid dynamics(CFD) method was used to study the influence of hullwaterjet interaction on propulsion performances of waterjet to research hullwaterjet interaction mechanism needed in speed and resistance prediction of waterjet propelled vessel. The threedimensional viscous flow fields of waterjets under openwater condition and mounted on hull with different deadrise angles and trim were obtained by calculating RANS equations closed by the kε turbulence model. The creditability of numerical model and method was validated by the good agreement between calculated results and test data. The results of different deadrise angle or list models showed that the deadrise angle or list had hardly any effect on the propulsion performance of waterjet. The results of different rocker angle or trim models showed that the rocker angle and trim made the hull boundary layer change, and had a notable influence on the propulsion performance and effect factors of the waterjet. With trim angle changing from positive to negative, the utilization of hull boundary layer by the waterjet increased, so the mass flow through waterjet decreased; however, the power, thrust and head increased. Besides, the momentum velocity coefficient, energy velocity coefficient, momentum interaction efficiency and energy interaction efficiency were decreased, too. However, the waterjet counteracted the hull by producing torque to whittle the trim angle.
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    ThreeDimensional Simulation of Water Hammer of LargeScale Water Conveyance Tunnel
    WANG Xiaoqinga,b,JIN Xianlonga,b,CAO Yuana
    2016, 50 (01):  98-102. 
    Abstract ( 780 )   Save
    Abstract: To study the water hammer phenomena of the largescale water conveyance tunnel, a threedimensional water hammer analysis method was proposed based on the ALE (arbitrary LagrangianEulerian) fluid structure interaction technique. The validity of the method was verified by comparing the simulation and experimental results of a case. Based on the multiscale simulation technique, the soilstructurewater coupled threedimensional nonlinear finite element model of a largescale water conveyance tunnel was established. Besides, its calculation was accomplished using the proposed method in combination with the mixed time explicit integration algorithm and its parallel technique. The results show that water hammer pressure decreases with the increase of valve closing time and shortening of tunnel length, and that the lining structure bearing maximum influence under water hammer is near the outlet of the tunnel.
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    Approach of Viscous/Potential Flow Based on Helmholtz Velocity Decomposition
    ZHAO Ji,ZHU Renchuan,MIAO Guoping
    2016, 50 (01):  103-109. 
    Abstract ( 913 )   Save
    Abstract: According to Helmholtz velocity decomposition, a modified NavierStokes(NS) equation was obtained by decomposing the velocity into the potential flow component and the remaining one. The solution to the modified NS equation was only for the remaining velocity component which vanished in the far field. It was highly efficient to solve the modified NS equation due to the request of small computation domain. Such viscous/potential flow solver was developed on the platform of open source software OpenFOAM. The flows around a cylinder were simulated by the present method in which the analytical formula was taken as the solution to the potential flow. The calculations of the flow around a cylinder at different Reynolds numbers and the comparison of the results with the ones obtained by using the conventional computational fluid dynamics method and the experiment data were conducted. The results agree well, which indicates that the present method is suitable to solve both laminar and turbulence flow and it can improve the computational efficiency.
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    Structural Design Method for Submarine Pressure Hull Based on Risk Beyond Submerged Depth
    BAI Xu
    2016, 50 (01):  110-114. 
    Abstract ( 913 )   Save
    Abstract: In this paper, a riskbased structural design method was discussed according to the risk beyond the submerged depth of submarines in the process of diving. First, the development of the structural design theory was expounded and the idea of riskbased structural design was presented. Then, the risk beyond the submerged depth was defined and the riskbased structural design criteria was developed according to the risk attitude of individuals, society, economy and the environment. Finally, the risk probability on different diving depths were calculated using the extreme value I distribution. The reliability optimization design model of the pressure hull was established and the design load curves with the increase of pressure hull structural weight was drawn. The design scheme for pressure hull was made based on the “costbenefit” principle.
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    Numerical Simulation of Planar Motion Mechanism Test and Hydrodynamic Derivatives of a Ship in Laterally Restricted Water
    LIU Hana,MA Ninga,b,SHAO Chuanga,GU Xiechonga,b
    2016, 50 (01):  115-122. 
    Abstract ( 1194 )   Save
    Abstract: To investigate the hydrodynamic characteristics of a large ship in laterally restricted water, this paper simulated the PMM test based on the computational fluid dynamics(CFD) technique. In order to realize the dynamic simulation of the planar motion mechanism(PMM) test limited by water width, a hybrid dynamic mesh technique was proposed. The proposed method was validated by comparing the numerical results with results of the PMM test in a circulating water channel. The PMM tests for different widths were simulated to analyze the relationship between hydrodynamic forces and motional velocities. The results show that the nonlinear feature of hydrodynamic forces becomes more remarkable in laterally restricted waters. The acceleration derivatives increase whereas the damping derivatives decrease, and a slight increment appears in the absolute values of rotational derivatives. The second order derivatives change drastically.
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    Optimization and RealTime Adjustment for Vehicle Routing Problem with Fuzzy Demand
    ZHANG Xiaonan,FAN Houming
    2016, 50 (01):  123-130. 
    Abstract ( 1207 )   Save
    Abstract: The vehicle routing problem with fuzzy demand was studied. In preoptimized phase with unknown demand, a preoptimized model was presented based on the credibility theory, and a variable neighborhood scatter search algorithm combining scatter search with variable neighborhood search was designed. In realtime adjusted phase with known demand, a novel realtime adjusted strategy was proposed, and a stochastic simulation algorithm was used to simulate the actual demands in the possible realtime scenarios. The results of computational experiments show that the designed algorithm and the proposed strategy have better performances.
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    A Method for Ship Compartment Layout Design Based on Gravitational Search Algorithm
    WANG Yu,HUANG Sheng,LIAO Quanmi,YANG Fangqing
    2016, 50 (01):  131-139. 
    Abstract ( 868 )   Save
    Abstract: A novel method for ship compartment layout design on multideck of one section of the hull was proposed, based on the design specification, statistical laws, conclusion of design experience and the related theory, and by using the utility theory and the improved multimodal optimization gravitational search algorithm based on the niche technology. The method can generate designs through the optimization calculation when noise, area and other parameters are inputted into it. The results from a series of optimization calculation tests show that the proposed design method are able to meet the requirements, and the improved gravitational search algorithm has a stable multimodal search capability.
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    Sailing Safety Based on SurfRiding Broaching Vulnerability Criteria
    ZHANG Baoji1,LU jiang2,GU min2
    2016, 50 (01):  140-144. 
    Abstract ( 990 )   Save
    Abstract: In order to assure the safety of ships sailing in the storm, the International Maritime Organization (IMO) has developed vulnerability criteria to assess whether the surfriding/broaching occurred to a ship or not. The proposal of vulnerability criteria to the second layer of surfriding/broaching by Japanese scholars in the conference of IMO SLF55/INF.15 was analyzed to compile a calculating program by using Maple, a mathematical tool. Taking a container ship, an oil tanker and a fishery ship as examples, the vulnerability criteria was calculated, and the probability of occurrence of surfriding broaching was determined. The results were used to verify the applicability and versatility of this program, which laid a foundation for the revision of the second generation intact stability criteria.
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    Buckling Analysis and Experiment of Cantilever ThinWalled Lenticular CFRP Space Boom
    CAI Qiyao1,CHEN Wujun1,ZHANG Daxu1,PENG Fujun2,FANG Guangqiang2
    2016, 50 (01):  145-151. 
    Abstract ( 1082 )   Save
    Abstract: The thinwalled lenticular CFRP (Carbon Fiber Reinforced Plastic)space boom operates as a cantilever. The two symmetry axils of cross section were taken as neutral axils respectively. The loading tests were performed and the load was applied at the cantilever tip. The external buckling load and the stability of the cantilever lenticular boom were obtained simultaneously. A linear eigenvalue buckling analysis was performed by using the ABAQUS, the linear buckling modes were seeded subsequently as an initial geometrical imperfection of the boom, and the nonlinear buckling analysis was conducted finally with load at the cantilever end. The results show that the initial geometrical imperfection has significant effects on buckling behavior while the proper geometrical imperfection seeded to the ideal perfect model can simulate the practical boom. A parametric analysis was done to evaluate the critical buckling load and buckling behavior, such as thickness, number of plies and slenderness. This paper can provide valuable reference for the optimization design of thinwalled CFRP lenticular spaceboom.
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    Nested Wave Numerical Simulation of Unstructured Mesh
    ZHU Zhixia
    2016, 50 (01):  152-157. 
    Abstract ( 881 )   Save
    Abstract: In order to accurately simulate the wave propagation of waterway and basin area in the estuary of Sheyang River, first, based on the application of unstructured triangular mesh of the third generation wave model SWAN and using the unstructured grid nesting technology, a large area and shallow engineering nested sea wave mathematical model was established. Then, the large and small computational domain wave numerical models were veryfied and the calculated values and measured values agreed well. Finally, the various cases of harbor basin and channel wave parameter were calculated, providing a scientific basis for the design department. The research results show that by applying the nested grid technology, on the one hand, the number of grid computing field was greatly reduced and the compution speed was increased. On the other hand, more intensive computing grid which can adapt to the complex topography and winding coastline of the border can be constructed, thus, raising the accuracy of the calculation results.
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    Durability Degradation Analysis of Raymond Cylinder Pile
    WU Feng1,2,WANG Dongdong2,SHI Beiling2,GONG Jinghai1,FU Kun2
    2016, 50 (01):  158-164. 
    Abstract ( 886 )   Save
    Abstract: In this paper, the initial boundary conditions for Raymond cylinder pile durability degradation was obtained from indoor test, and status information of the durability degradation was obtained from field sampling. Field investigation and pile body sampling were made to obtain the concrete chloride ion concentration profile of large pipe piles in service for 1 to 17 years. The degradation model for Raymond cylinder pile was built by a mathematic formula of Fick’s second law. The corrosion parameters of large pipe pile, such as the chloride ion diffusion coefficient, were obtained based on the statistical analysis of large amounts of data. Concrete chloride ion penetrations of the pile body and pile cap were compared and analyzed. The durability degradation law of Raymond cylinder pile was given, providing reference for large pipe pile durability design, use and maintenance.
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