plaxis中文参考手册

参考手册目录1简介 (7)2 一般说明 (7)2.2 文件处理 (9)2.3 帮助工具 (9)2.4 输入方法 (10)3 输入前处理 (10)3.1 输入程序 (10)3.5 荷载和边界条件 (28)4 材料属性和材料数据组 (33)4.1 模拟土体及界面行为 (35)4.1.1 一般标签页 (35)4.1.2 参数标签页 (39)4.1.3 渗流参数标签页 (50)4.1.4 界面标签页 (56)4.1.5 初始标签页 (61)4.2 不排水行为模拟 (63)4.2.1 不排水（A） (64)4.2.2 不排水（B） (64)4.2.3 不排水（C） (64)4.3 土工试验模拟 (64)4.3.1 三轴试验 (67)4.3.2 固结仪试验 (68)4.3.3 CRS (68)4.3.4 DDS (69)4.3.6 结果 (70)4.4 板的材料数据组 (70)4.4.1 材料数据组 (71)4.4.2 属性 (71)4.5.1 材料数据组 (74)4.5.2 属性 (74)4.6 锚杆的材料数据组 (75)4.6.1 材料数据组 (76)4.6.2 属性 (76)4.7 几何构件的材料数据组赋值 (76)5 计算 (77)5.1 计算程序界面 (77)5.2 计算菜单 (78)5.3 计算模式 (79)5.3.1 经典模式 (80)5.3.2 高级模式 (80)5.3.3 渗流模式 (81)5.4 定义计算阶段 (81)5.4.1 计算标签页 (81)5.4.2 插入或删除计算阶段 (82)5.4.3 计算阶段的标识和顺序 (82)5.5 分析类型 (83)5.5.1 初始应力生成 (83)5.5.2 塑性计算 (85)5.5.3塑性（排水）计算 (85)5.5.4 固结（EPP）分析 (85)5.5.5 固结（TPP）分析 (86)5.5.6 安全性（PHI/C折减） (86)5.5.7 动力分析 (87)5.5.8 自由振动 (87)5.5.9 地下水渗流（稳态） (88)5.5.10 地下水渗流（瞬态） (88)5.5.11 塑性零增长步 (88)5.6 加载步骤 (90)5.6.1 自适应步长法 (90)5.6.2 加载终极水平法 (90)5.6.3 加载步数法 (91)5.6.4 自适应步长（固结） (92)5.7 计算控制参数 (92)5.7.1 迭代过程控制参数 (93)5.7.2 孔压限定 (97)5.7.3 荷载输入 (97)5.7.4 控制参数 (100)5.8 分步施工‐几何定义 (102)5.8.1 改变几何模型 (102)5.8.2 激活或冻结类组或结构对象 (103)5.8.3 激活或改变荷载 (103)5.8.4 应用指定位移 (104)5.8.5 材料数据组重新赋值 (105)5.8.6 在块类组上施加体积应变 (105)5.8.7 施加锚杆预应力 (106)5.8.8 施加隧道衬砌收缩 (106)5.8.9 ΣMstage < 1 的分步施工 (107)5.8.10 未完成的分步施工计算 (108)5.9 分步施工‐水力条件 (109)5.9.1 水的单位重度 (109)5.9.2 潜水位 (109)5.9.3 封闭边界 (113)5.9.4 降水 (113)5.9.5 类组水位分布 (114)5.9.6 渗流和固结边界条件 (115)5.9.7 特殊对象 (115)5.10 荷载乘子 (115)5.10.1 标准荷载乘子 (116)5.10.2 其它乘子和计算参数 (118)5.10.3 动力乘子 (119)5.11敏感性分析&参数变化 (120)5.11.1敏感性分析 (121)5.11.2参数变化 (121)5.11.3定义参数变化 (121)5.11.5 敏感度—查看结果 (123)5.11.6 参数变化 — 计算边界值 (125)5.11.7 查看上下限 (125)5.11.8 查看变化结果 (125)5.11.9 删除结果 (126)5.12 执行计算 (126)5.12.1 预览施工阶段 (126)5.12.2 选定曲线点 (126)5.12.3 执行计算过程 (126)5.12.4 放弃计算 (127)5.12.5 计算过程中输出 (127)5.12.6 选择拟输出计算阶段 (130)5.12.7 重置分步施工设置 (130)5.12.8 计算过程中调整输入数据 (131)5.12.9 自动误差检验 (131)6 输出程序‐概览 (133)6.1 输出程序的界面 (134)6.2 菜单栏中的菜单 (135)6.3 输出程序中的工具 (138)6.4绘图区 (144)6.5 输出的视图 (147)6.6报告生成 (148)6.7生成动画 (151)7 输出程序中的可用结果 (152)8曲线 (161)1简介PLAXIS 2D是一个专门用于各种岩土工程问题中变形和稳定性分析的二维有限元计算程序。

P LAXIS 2D Dynamics Manual Version 9.0TABLE OF CONTENTS TABLE OF CONTENTS1Introduction..................................................................................................1-11.1About this manual..................................................................................1-11.2Dynamic loading features......................................................................1-2 2Tutorial.........................................................................................................2-12.1Dynamic analysis of a generator on an elastic foundation.....................2-12.1.1Input...........................................................................................2-12.1.2Initial conditions........................................................................2-42.1.3Calculations................................................................................2-52.1.4Output........................................................................................2-72.2Pile driving.............................................................................................2-92.2.1Initial conditions......................................................................2-122.2.2Calculations..............................................................................2-122.2.3Output......................................................................................2-142.3Building subjected to an earthquake....................................................2-152.3.1Initial conditions......................................................................2-172.3.2Calculations..............................................................................2-172.3.3Output......................................................................................2-19 3Reference......................................................................................................3-13.1Input.......................................................................................................3-13.1.1General settings..........................................................................3-23.1.2Loads and Boundary conditions.................................................3-33.1.3Absorbent boundaries................................................................3-33.1.4External loads and Prescribed displacements.............................3-33.1.5Model parameters.......................................................................3-53.2Calculations...........................................................................................3-83.2.1Selecting dynamic analysis........................................................3-83.2.2Dynamic analysis parameters.....................................................3-83.2.3Iterative procedure manual setting.............................................3-93.2.4Dynamic loads.........................................................................3-113.2.5Activating Dynamic loads........................................................3-113.2.6Harmonic loads........................................................................3-123.2.7Load multiplier time series from data file................................3-133.2.8Modelling block loads..............................................................3-153.3Output..................................................................................................3-153.4Curves..................................................................................................3-16 4Validation and verification of the dynamic module..................................4-14.1One-dimensional wave propagation.......................................................4-14.2Simply supported beam..........................................................................4-34.3Determination of the velocity of the Rayleigh wave..............................4-5iDYNAMICS MANUAL4.4Lamb’s problem.....................................................................................4-74.5Surface waves: Comparison with boundary elements.........................4-114.6Pulse load on a multi layer system.......................................................4-12 5Theory...........................................................................................................5-15.1Basic equation dynamic behaviour........................................................5-15.2Time integration....................................................................................5-25.2.1Wave velocities..........................................................................5-35.2.2Critical time step........................................................................5-45.3Model boundaries..................................................................................5-45.3.1Absorbent boundaries................................................................5-55.4Initial stresses and stress increments......................................................5-6 6References....................................................................................................6-1ii P LAXIS 2DINTRODUCTION 1INTRODUCTIONSoil and structures are often subjected not only to static loads due to constructions in and on the ground surface but also to dynamic loads. If the loads are powerful, as in earthquakes, they may cause severe damages. With the P LAXIS Dynamic analysis module you can analyse the effects of vibrations in the soil.Vibrations may occur either manmade or natural. In urban areas, vibrations can be generated due to pile driving, vehicle movement, heavy machinery and/or train travel. A natural source of vibrations in the subsoil is earthquakes.The effects of vibrations have to be calculated with a dynamic analysis when the frequency of the dynamic load is in the order or higher than the natural frequency of the medium. Low frequency vibrations can be calculated with a pseudo-static analysis.In modelling the dynamic response of a soil structure, the inertia of the subsoil and the time dependence of the load are considered. Also, damping due to material and/or geometry is taken into account. Initially the Linear-elastic model can be utilised for the simulation of the dynamic effects, but in principle any of the available soil models in P LAXIS can be used.Excess pore pressures can be included in the analysis if undrained soil behaviour is assumed. Liquefaction, however, is not considered in P LAXIS 2D. Future versions may incorporate a model that is able to simulate this phenomenon.Even though vibrations often have 3D-characteristics, in P LAXIS 2D, the dynamic model is limited to plane strain and axisymmetric conditions.The dynamic calculation program was developed in cooperation with the University of Joseph Fourier in Grenoble. This cooperation is gratefully acknowledged.1.1ABOUT THIS MANUALThis manual will help the user to understand and work with the P LAXIS Dynamics module. New users of P LAXIS are referred to the Tutorial Manual first (P LAXIS 2D). Tutorial ChaptersThe Dynamics manual starts with a tutorial section. The user is advised to work through the exercises. In the first exercise the influence of a vibrating source over its surrounding soil is studied. The second exercise deals with the effects of pile driving. The third exercise analyse the effect of an earthquake on a five-storey building.Reference ChaptersThe second part of the Dynamics manual consists of four chapters. These chapters describe the four parts of the P LAXIS Program (input, calculation, output and curves) in view of the functionality of the Dynamics module.1-1DYNAMICS MANUALValidation/Verification ChaptersThe third part of the manual describes some of the test cases that were used to validate the accuracy and performance of the dynamics module.Theory ChaptersIn the fourth part of the manual you will find a brief review of the theoretical aspects of the dynamic model as used and implemented in P LAXIS.1.2DYNAMIC LOADING FEATURESThe way dynamic loads in P LAXIS are applied during calculations is similar but not exactly equal to version 7 and older. The creation and generation of dynamic loads is summarized below:1.In the Input program:•create loads such as load system A or B and/or prescribed displacements.•set the appropriate load (load system A, B and/or prescribed displacements) asa dynamic load using the Loads menu2.In the Calculation program:•activate dynamic loads using the dynamic load Multipliers input window in the Multipliers tab sheet. An active button will appear for each load.Unlike the way static loads are defined (using Staged construction) dynamic loads are defined by means of the dynamic Multipliers. These Multipliers operate as scaling factors on the input values of the dynamic loads (as entered in the Input program) to produce the actual load magnitudes. If a particular load system is set as a dynamic load, the load is initially kept active, but the corresponding load multiplier is set to zero in the Input program. In the Calculation program, it is specified how the (dynamic) load multiplier changes with time rather the input value of the load. The time dependent variation of the load multiplier acts on all loads in the corresponding load system.1-2 P LAXIS 2DTUTORIAL 2TUTORIALThis tutorial is intended to help users to become familiar with the features of the P LAXIS dynamics module. New users of P LAXIS are referred to the Tutorial Manual of the complete P LAXIS 2D manual first. The lessons in this part of the Dynamics manual deal with three specific dynamic applications of the program.Generator on elastic foundation•an axisymmetric model for single source vibrations•dynamic soil-structure interaction•standard absorbent boundariesPile driving•plastic behaviour•influence of waterBuilding subjected to an earthquake• a plane strain analysis for earthquake problems•SMC file used for acceleration input•standard earthquake boundaries2.1DYNAMIC ANALYSIS OF A GENERATOR ON AN ELASTICFOUNDATIONUsing P LAXIS,it is possible to simulate soil-structure interaction. Here the influence of a vibrating source on its surrounding soil is studied.Due to the three dimensional nature of the problem, an axisymmetric model is used. The physical damping due to the viscous effects is taken into consideration via the Rayleigh damping. Also, due to axisymmetry 'geometric damping' can be significant in attenuating the vibration.The modelling of the boundaries is one of the key points. In order to avoid spurious wave reflections at the model boundaries (which do not exist in reality), special conditions have to be applied in order to absorb waves reaching the boundaries.2.1.1INPUTThe vibrating source is a generator founded on a 0.2 m thick concrete footing of 1 m in diameter, see Figure 2.1. Oscillations caused by the generator are transmitted through the footing into the subsoil. These oscillations are simulated as a uniform harmonic loading, with a frequency of 10 Hz and amplitude of 10 kN/m2. In addition to the weight2-1DYNAMICS MANUALof the footing, the weight of the generator is assumed 8 kN/m2, modelled as a uniformly distributed load.Figure 2.1 Generator founded on elastic subsoil.Geometry modelThe problem is simulated using an axisymmetric model with 15-noded elements. The geometry model is shown in Figure 2.2. Use [s] (seconds) as the unit of time, since dynamic effects are usually in the order of seconds rather than days.The model boundaries should be sufficiently far from the region of interest, to avoid disturbances due to possible reflections. Although special measures are adopted in order to avoid spurious reflections (absorbent boundaries), there is always a small influence and it is still a good habit to put boundaries far away. In a dynamic analysis, model boundaries are generally taken further away than in a static analysis.To set up the problem geometry, the following steps are necessary:•Enter the geometry model as shown in Figure 2.2.•Use plate elements to model the footing.•Use Standard fixities.•Apply a distributed load (system A) on the footing to model the weight of the generator.•Apply a distributed load (system B) on the footing to model the dynamic load.•In the Loads menu, set the Dynamic load system to load system B.Absorbent boundariesSpecial boundary conditions have to be defined to account for the fact that in reality the soil is a semi-infinite medium. Without these special boundary conditions the waves would be reflected on the model boundaries, causing perturbations. To avoid these spurious reflections, absorbent boundaries are specified at the bottom and right hand side boundary.2-2 P LAXIS 2DTUTORIAL 2-3To add the absorbent boundaries you can use the Standard absorbent boundaries optionin the Loads menu. If necessary, the absorbent boundaries can be generated manually as:1. Select the menu option Absorbent boundaries in the Loads menu.2. Click on the lower left point of the geometry,3. Proceed to the lower right point and click again,4. Proceed to the upper right point and click again.Only the right and bottom boundaries are absorbent boundaries. The left boundary is anaxis of symmetry and the upper boundary is a free surface.Figure 2.2 Generator model with absorbent boundariesMaterial propertiesThe properties of the subsoil are given in Table 2.1. It consists of sandy clay, which isassumed to be elastic. The Young’s modulus in Table 2.1 seems relatively high. This isbecause the dynamic stiffness of the ground is generally considerably larger than thestatic stiffness, since dynamic loadings are usually fast and cause very small strains. Theunit weight suggests that the soil is saturated; however the presence of the groundwateris neglected. The footing has a weight of 5 kN/m 2 and is also assumed to be elastic. Theproperties are listed in Table 2.2.Table 2.1 Material properties of the subsoil Parameter Name Value Unit Material model Model Elastic -Type of material behaviour Type Drained -Unit weight γ20.0 kN/m 3 Young's modulus (constant) E ref 50000 kN/m 2Poisson's ratio ν0.3 -DYNAMICS MANUAL2-4 P LAXIS 2D Table 2.2 Material properties of the footing Parameter Name Value Unit Normal stiffness EA 7.6 · 106 kN/m Flexural rigidity EI 24000 kNm 2/mWeight W 5.0 kN/m/mPoisson's ratio ν0.0 - Hint: When using Mohr-Coulomb or linear elastic models the wave velocities V pand V s are calculated from the elastic parameters and the soil weight. V p andV s can also be entered as input; the elastic parameters are then calculatedautomatically. See also Elastic parameters in Section 3.1.5 and the WaveVelocity relationships in Section 5.2.1.Mesh generationBecause of the expected high concentration of stresses in the area below the footing, alocal refinement is proposed there. The mesh is generated with the global coarseness setto ‘coarse’ and then the line of the footing is refined two times. The result is plotted inFigure 2.3.Figure 2.3 Geometry and mesh2.1.2 INITIAL CONDITIONSWater pressures:Since water is not considered in this example, the generation of water pressures can beskipped.Initial stresses:The initial stresses are generated by means of the K0 procedure , using a K 0 value of 0.5.In the initial situation, the footing and the static load do not exist and therefore they aredeactivated. The dynamic load seems active but the corresponding multiplier isautomatically set to zero.2.1.3CALCULATIONSThere are three calculation phases. In the first phase the footing is built and the static load (weight of the generator) is applied. The second phase is the situation when the generator is running. In the third phase the generator is turned off and the soil is let to vibrate freely. The last two phases involve dynamic calculations.Phase 1:1.Select Plastic calculation in the General tab sheet.2.Select Staged construction in the Parameter tab sheet and click on the Definebutton3.Click on the plate element and select all objects from the Select items window. Byusing the Change option, set the static load (system A) to 8 kN/m2. Note that this value can also be set in the Input program (see the Reference Manual).Phase 2:In this phase, a vertical harmonic load, with a frequency of 10 Hz and amplitude of 10 kN/m2, is applied to simulate the vibrations transmitted by the generator. Five cycles with a time interval of 0.5 sec are considered.1.Select Dynamic analysis in the General tab sheet.e 100 for the number of Additional steps, reset displacement to zero and set Timeinterval to 0.5 s.3.Select Total multipliers and click on the Define button.4.Click on (next to ΣMloadB in the Multipliers tab sheet) to proceed with thedefinition of the dynamic load.5.Click the option Harmonic load multiplier in the window Dynamic loading-LoadSystem B.6.Set the Amplitude multiplier to 10, frequency to 10 Hz and Initial phase angle to 0(See Figure 2.4).Figure 2.4 Harmonic loadPhase 3:In this phase, the generator is turned off. The soil is vibrating freely after the initial excitation.1.Select Dynamic analysis in the General tab sheet.e 100 for the number of Additional steps.3.Set Time interval to 0.5 s. The estimated end time is 1 sec.4.Select Total multipliers and click on the Define button.5.Click on next to ΣMloadB in the Multipliers tab sheet. Set all parameters tozero in the Dynamic loading window.Before running the calculation, select points at the surface at about 1.4m, 1.9m and 3.6m. They will be used by the Curves program to visualise the deformation as a function of time. You can now start the calculation.Additional calculation with damping:In a second calculation, material damping is introduced by means of Rayleigh damping. Rayleigh damping can be entered in the material data set. The following steps are necessary:1.Start the Input program and select the generator project.2.Save the project under another name.3.Open the material data set of the soil. In the General tab sheet click on theAdvanced button.4.Change the Rayleigh damping parameters α and β to 0.001 and 0.01 respectively(Figure 2.5).Figure 2.5 Input of Rayleigh damping5.Close the data base, proceed to Initial conditions and save the project.6. In the Calculations program, check whether the phases are still properly defined(according to the information given before) and start the calculation.2.1.4 OUTPUTThe Curves program is particularly useful for dynamic analysis. You can easily displaythe actual loading versus time (input) and also displacements, velocities andaccelerations of the pre-selected points versus time. Figure 2.6 shows the evolution ofthe applied load with time, as defined by the calculation phases 2 and 3.-10-55D i i []Load system BFigure 2.6 Load – time curve0.0Time [s]Displacement [m]Figure 2.7 Displ.- time on the surface at different distances to the vibrating source.Without damping (Rayleigh α = 0; β = 0).Figure 2.7 shows the response of the pre-selected points at the surface of the structure. Itcan be seen that even with no damping, the waves are dissipated which can be attributedto the geometric damping.0.0Time [s]Figure 2.8 Displ.- time. With damping (Rayleigh α = 0.001 ; β = 0.01).The presence of damping is clear in Figure 2.8. It can be seen that the vibration is totallyseized after the removal of the force (after t = 0.5 s). Also, the displacement amplitudesare lower. Compare Figure 2.7 (without damping) with Figure 2.8 (with damping).Figure 2.9 Total accelerations in the soil at the end of phase 2 (with damping).It is possible in the Output program to display displacements, velocities and accelerations at a particular time, by choosing the appropriate option in the Deformations menu. Figure 2.9 shows the total accelerations in the soil at the end of phase 2 (t = 0.5 s).2.2PILE DRIVINGThis example involves driving a concrete pile through an 11 m thick clay layer into a sand layer, see Figure 2.10. The pile has a diameter of 0.4 m. Pile driving is a dynamic process that causes vibrations in the surrounding soil. Moreover, excess pore pressures are generated due to the quick stress increase around the pile.In this example focus is placed on the irreversible deformations below the pile. In order to simulate this process most realistically, the behaviour of the sand layer is modelled by means of the Hardening Soil model.Figure 2.10 Pile driving situationGeometry modelThe geometry is simulated by means of an axisymmetric model in which the pile is positioned along the axis of symmetry (see Figure 2.11). In the general settings, the standard gravity acceleration is used (9.8 m/s2). The unit of time should be set to seconds [s].Both the soil and the pile are modelled with 15-noded elements. The subsoil is divided into an 11 m thick clay layer and a 7 m thick sand layer. Interface elements are placed around the pile to model the interaction between the pile and the soil. The interface should be extended to about half a meter into the sand layer (see Figure 2.12). A proper modelling of the pile-soil interaction is important to include the material dampingcaused by the sliding of the soil along the pile during penetration and to allow forsufficient flexibility around the pile tip. Use the zoom option to create the pile and theinterface.Figure 2.11 Geometry model of pile driving problemThe boundaries of the model are taken sufficiently far away to avoid direct influence ofthe boundary conditions. Standard absorbent boundaries are used at the bottom and atthe right hand boundary to avoid spurious reflections. Hint: When boundary conditions are applied using the Standard fixities button,horizontal fixities are also applied to the pile top. The standard fixities optionassigns fixities to all lines that lie witin certain limits from the boundaries ofthe geometry and as, due to its dimensions, the pile top falls within theselimits, boundary conditions are applied. Since this is not desired make sure toremove the horizontal fixities at the pile top.In order to model the driving force, a distributed unit load (system A) is created on topof the pile. From the Loads menu set Load system Aas a dynamic load system.(0.0, 7.0)Figure 2.12 Extended InterfaceMaterial propertiesThe clay layer is modelled with the Mohr-Coulomb model. The behaviour is consideredto be undrained. An interface strength reduction factor is used to simulate the reduced friction along the pile shaft.In order to model the non-linear deformations below the tip of the pile in a right way,the sand layer is modelled by means of the Hardening Soil model. Because of the fastloading process, the sand layer is also considered to behave undrained. The short interface in the sand layer does not represent soil-structure interaction. As a result, theinterface strength reduction factor should be taken equal to unity (rigid).The pile is made of concrete, which is modelled by means of the linear elastic model considering non-porous behaviour. In the beginning, the pile is not present, so initiallythe clay properties are also assigned to the pile cluster. The parameters of the two layersand the concrete pile are listed in Table 2.3.Table 2.3 Material properties of the subsoil and pileParameter Symbol Clay Sand Pile Unit Material model Model Mohr-C. Hardening-S Linear elast. -Type of behaviour Type Undrained Undrained Non-porous -Unit weight aboveγunsat16 17 24 kN/m3 phreatic lineUnit weight below18 20 - kN/m3 phreatic line γsatYoung's modulus E ref15000 50000 3·107 kN/m2Oedometer modulus E oed- 50000 - kN/m2 Power m - 0.5 - -- kN/m2 Unloading modulus E ur- 150000Poisson's ratio ν0.3 0.2 0.1 - Reference stress P ref- 100 - kN/m2 Cohesion c 2 1 - kN/m2 Friction angle ϕ24 31 - °Dilatancy angle ψ0 0 - °Interface strengthR inter0.5 1.0 (rigid) 1.0 (rigid) - reductionIt should be noted that there is a remarkable difference in wave velocities between the clay layer and the concrete pile due to the large stiffness difference. This may lead to small time increments (many sub steps) in the automatic time stepping procedure. This causes the calculation process to be very time consuming. Many sub steps may also be caused by a very small (local) element size. In such situations it is not always vital to follow the automatic time stepping criterion. You can reduce the number of sub steps inthe Manual setting of the Iterative procedure (Section 3.2.3).When the Hardening Soil model is used wave velocities are not shown because they vary due to the stress-dependent stiffness.Mesh generationThe mesh is generated with a global coarseness set to coarse (default). A local refinement is made in the pile cluster. The result of the mesh generation is plotted in Figure 2.13.18yFigure 2.13 Finite element mesh for pile driving problem.2.2.1INITIAL CONDITIONSWater pressures:The phreatic level is assumed to be at the ground surface. Hydrostatic pore pressures are generated in the whole geometry according to this phreatic line.Initial stresses:Initial effective stresses are generated by the K0procedure, using the default values. Note that in the initial situation the pile does not exist and that the clay properties should be assigned to the corresponding clusters.2.2.2CALCULATIONSThe analysis consists of three calculation phases. In the first phase the pile is created. In the second phase the pile is subjected to a single stroke, which is simulated by activating half a harmonic cycle of load system A. In the third phase the load is kept zero and the dynamic response of the pile and soil is analysed in time. The last two phases involve dynamic calculations.Phase 1:1.Select Plastic calculation in the General tab sheet.2.Select Staged construction in the Parameter tab sheet.3.Assign the pile properties to the pile cluster.Phase 2:1.Select Dynamic analysis in the General tab sheet.e standard Additional steps (250).3.Reset displacements to zero.4.Enter 0.01 s for the Time interval.5.Select Manual setting for the iterative procedure and click Define. The initialnumber of Dynamic sub steps is relatively large, due to the large difference in wave speeds and the small element sizes (see earlier remark on material properties). Set the number of Dynamic sub steps to 1. All other settings remain at their default. 6.Click next to Load system A in the Multiplier tab sheet to apply the dynamicloading. Enter the values as indicated in Figure 2.14.Figure 2.14 Dynamic loading parametersThe result of this phase is half a harmonic cycle of the external load in system A. At the end of this phase, the load is back to zero.Phase 3:1.Select Dynamic analysis in the General tab sheet.e standard Additional steps (250).3.Enter a Time interval of 0.19 s.4.Select the Manual setting for the Iterative procedure and click Define. Set thenumber of Dynamic sub steps to 19. This results in equal time steps in phase 2 and3.5.In the Multiplier tab sheet, all multipliers remain at their default values.6.Click next to Load system A and set all parameters in the Dynamic Loadingwindow to zero.。

中⽂参考⼿册-PLAXIS2D--岩⼟三维建模分析参考⼿册⽬录1简介 (7)2 ⼀般说明 (7)2.2 ⽂件处理 (9)2.3 帮助⼯具 (9)2.4 输⼊⽅法 (10)3 输⼊前处理 (10)3.1 输⼊程序 (10)3.5 荷载和边界条件 (28)4 材料属性和材料数据组 (33)4.1 模拟⼟体及界⾯⾏为 (35)4.1.1 ⼀般标签页 (35)4.1.2 参数标签页 (39)4.1.3 渗流参数标签页 (50)4.1.4 界⾯标签页 (56)4.1.5 初始标签页 (61)4.2 不排⽔⾏为模拟 (63)4.2.1 不排⽔（A） (64)4.2.2 不排⽔（B） (64)4.2.3 不排⽔（C） (64)4.3 ⼟⼯试验模拟 (64)4.3.1 三轴试验 (67)4.3.2 固结仪试验 (68)4.3.3 CRS (68)4.3.4 DDS (69)4.3.6 结果 (70)4.4 板的材料数据组 (70)4.4.1 材料数据组 (71)4.4.2 属性 (71)4.5.1 材料数据组 (74)4.5.2 属性 (74)4.6 锚杆的材料数据组 (75)4.6.1 材料数据组 (76)4.6.2 属性 (76)4.7 ⼏何构件的材料数据组赋值 (76)5 计算 (77)5.1 计算程序界⾯ (77)5.2 计算菜单 (78)5.3 计算模式 (79)5.3.1 经典模式 (80)5.3.2 ⾼级模式 (80)5.3.3 渗流模式 (81)5.4 定义计算阶段 (81)5.4.1 计算标签页 (81)5.4.2 插⼊或删除计算阶段 (82)5.4.3 计算阶段的标识和顺序 (82) 5.5 分析类型 (83)5.5.1 初始应⼒⽣成 (83)5.5.2 塑性计算 (85)5.5.3塑性（排⽔）计算 (85)5.5.4 固结（EPP）分析 (85)5.5.5 固结（TPP）分析 (86)5.5.6 安全性（PHI/C折减） (86) 5.5.7 动⼒分析 (87)5.5.8 ⾃由振动 (87)5.5.9 地下⽔渗流（稳态） (88)5.5.10 地下⽔渗流（瞬态） (88) 5.5.11 塑性零增长步 (88)5.6 加载步骤 (90)5.6.1 ⾃适应步长法 (90)5.6.2 加载终极⽔平法 (90)5.6.3 加载步数法 (91)5.6.4 ⾃适应步长（固结） (92)5.7 计算控制参数 (92)5.7.1 迭代过程控制参数 (93)5.7.2 孔压限定 (97)5.7.3 荷载输⼊ (97)5.7.4 控制参数 (100)5.8 分步施⼯‐⼏何定义 (102)5.8.1 改变⼏何模型 (102)5.8.2 激活或冻结类组或结构对象 (103) 5.8.3 激活或改变荷载 (103)5.8.4 应⽤指定位移 (104)5.8.5 材料数据组重新赋值 (105)5.8.6 在块类组上施加体积应变 (105) 5.8.7 施加锚杆预应⼒ (106)5.8.8 施加隧道衬砌收缩 (106)5.8.9 ΣMstage < 1 的分步施⼯ (107) 5.8.10 未完成的分步施⼯计算 (108) 5.9 分步施⼯‐⽔⼒条件 (109)5.9.1 ⽔的单位重度 (109)5.9.2 潜⽔位 (109)5.9.3 封闭边界 (113)5.9.4 降⽔ (113)5.9.5 类组⽔位分布 (114)5.9.6 渗流和固结边界条件 (115)5.9.7 特殊对象 (115)5.10 荷载乘⼦ (115)5.10.1 标准荷载乘⼦ (116)5.10.2 其它乘⼦和计算参数 (118)5.10.3 动⼒乘⼦ (119)5.11敏感性分析&参数变化 (120)5.11.1敏感性分析 (121)5.11.2参数变化 (121)5.11.3定义参数变化 (121)5.11.5 敏感度—查看结果 (123)5.11.6 参数变化 — 计算边界值 (125) 5.11.7 查看上下限 (125)5.11.8 查看变化结果 (125)5.11.9 删除结果 (126)5.12 执⾏计算 (126)5.12.1 预览施⼯阶段 (126)5.12.2 选定曲线点 (126)5.12.3 执⾏计算过程 (126)5.12.4 放弃计算 (127)5.12.5 计算过程中输出 (127)5.12.6 选择拟输出计算阶段 (130)5.12.7 重置分步施⼯设置 (130)5.12.8 计算过程中调整输⼊数据 (131)5.12.9 ⾃动误差检验 (131)6 输出程序‐概览 (133)6.1 输出程序的界⾯ (134)6.2 菜单栏中的菜单 (135)6.3 输出程序中的⼯具 (138)6.4绘图区 (144)6.5 输出的视图 (147)6.6报告⽣成 (148)6.7⽣成动画 (151)7 输出程序中的可⽤结果 (152)8曲线 (161)1简介PLAXIS 2D是⼀个专门⽤于各种岩⼟⼯程问题中变形和稳定性分析的⼆维有限元计算程序。

PLAXIS基本知识备忘提示: 即使不满意网格生成的结果，也必须使用<更新>按钮返回到几何模型。

输入模式。

提示:网格全局疏密度的默认设置为粗。

大多数情况下，这是合适的首选。

> 全局疏密度的设置可以在网格菜单中加以修改。

另外，可以整体或局部加密网格。

在这一输入阶段，还可以调整部分几何对象或增加几何对象。

如果做出调整，必须重新生成有限元网格。

从网格菜单中,选择全局疏密,选项,这时单元分布下拉菜单的默认选项为粗。

为,加密全局疏密,,我们可以从下,菜单中选择下一个选项:中等:,然后点击<生成>按钮。

另外,我们也可以从网格菜单中,选择全局加密选项。

随后,输出视窗出现一个较细的网格。

然后,点击<更新>按钮返回。

结构单元拐角处的点可能产生很大的位移梯,,因此最好在这些区域内划分相对于几何模型其他部分,细的网格。

点击:单击:地下连续墙下部的中间,所选几何直线变为红色。

从网格菜单中选择加密线选项,所选线周围局部加密后的网格呈现视窗中。

之后,点击<更新>按钮返回。

网格设置和输入的其他部分保存在一起。

当再次进入一个现存项目而不改变其几何轮廓和网格设置时，可以通过点击工具栏中的生成网格按钮重新生成同样的网格。

不过，几何模型的任何轻微变化将导致不同的网格。

网格菜单中的全部重置选项用来恢复生成网格的默认设置(全局疏密度=粗并且没有局部加密)。

点击工具栏中的生成初始应,按钮:红十字:或在生成菜单中选择初始应,选项,出现K0-过程对话框。

保持土体容重的总乘子:ΣMweight,等于1.0_这意味着土的全部重,应用于生成初始应,。

接受PLAXIS 建议的K0 默认值并点击<确认>按钮。

提示:K0-过程只能应用于地基水平分层且表面水平，地下水位也是水平的情况。

关于K0-过程的详细知识，参见附录A 或参考手册。

K0 的默认值基于Jaky 公式:K0,1-sinφ。

修改默认值以后，输入一个负值可以恢复其默认值。

Plaxis注意点一．输入前说明1. 在平面应变分析里，由指定位移计算所得的力，是平面外单位长度上的力（z 方向，见图）。

轴对称分析计算所得的力（力-X，力-Y），是作用于对角弧度为1的圆弧边界上的力。

因而，要得到与整个问题对应的力，这些分力应当乘以因子2π。

轴对称分析问题的其他计算结果，是按单位宽度而不是按单位弧度给出的。

在所有输出数据里，压应力（包括孔隙压力）和压力设为负值，而拉应力和拉力设为正值。

二．输入前处理1. 平面应变模型，适用于断面(大致)均匀的几何形状，其中垂直于断面（z-方向）一定长度上的应力状态和加载机制是相同的。

z 轴方向上的位移和应变设为零。

但是，完全考虑了z 轴正应力。

轴对称模型，适用于径向断面（大致）均匀的圆形结构，加载机制围绕中心轴，设沿任意径向的变形和应力状态一致。

注意：轴对称问题的x坐标表示半径，y 坐标对应于对称轴线。

不能使用负x 坐标值。

选择平面应变或轴对称，意味着二维有限元模型的每个节点，只具备2个平移自由度（即x-和y-方向）。

2. 板用来模拟地层中的细长形结构对象，具有相当的抗弯刚度（或弯曲刚度）和轴向刚度。

板可以模拟沿z方向延伸的挡土墙、板、壳体或衬砌的影响。

最重要的参数是抗弯刚度（弯曲刚度）EI 和轴向刚度EA。

由以上两个参数可以用下式计算出板的等效厚度deq ：3. 土工格栅是具有轴向刚度而无弯曲刚度的细长形结构。

土工格栅只能承受拉力，不能承受压力。

该类对象一般用来模拟土体的加固作用。

和点对点锚杆相组合的土工格栅，可以用来模拟地层锚杆。

在这种组合情况下，土工格栅用来模拟锚杆的锚固段，而点对点锚杆用来模拟锚杆的自由段。

4. 用界面单元可以研究结构对象（挡土墙、板、土工格栅等）和周围土体之间充分的相互作用。

可以使用一个加号（+）或减号（-），来标注沿同一条几何线上可能出现的两个界面。

这里的加减号仅仅是为了区别不同界面，并没有什么物理意义，对计算结果也无影响。

动力模块手册Plaxis BV北京金土木软件技术有限公司北京海淀区首体南路9号主语国际中国建筑标准设计研究院 100044目 录1 简介 (1)1.1关于手册 (1)1.2 V8版本动力荷载特性 (1)2、指导 (3)2.1 弹性地基上振动装置振动分析 (3)2.1.1输入 (3)2.1.2 初始条件 (5)2.1.3 计算 (6)2.1.4 输出 (7)2.2 打桩 (9)2.2.1 初始条件 (11)2.2.2计算 (11)2.2.3输出 (13)2.3 建筑物经受地震 (14)2.3.1 初始条件 (16)2.3.2 计算 (16)2.3.3 输出 (17)3参考手册 (19)3.1输入 (19)3.1.1一般设置 (20)3.1.2荷载和边界条件 (20)3.1.3吸收边界 (21)3.1.4外部荷载和指定位移 (21)3.1.5模型参数 (22)3.2计算 (24)3.2.1选择动力分析 (24)3.2.2动力分析参数 (24)3.2.3迭代过程手动设置 (25)3.2.4动力荷载 (26)3.2.5激活动力荷载 (27)3.2.6简谐荷载 (27)3.2.7数据文件中的荷载乘子时间数列 (28)3.2.8模型基本荷载 (30)3.3输出 (30)3.4曲线 (31)4 动力模块的校验 (33)4.1单向波的传播 (33)4.2简支梁 (35)4.3雷利波速的确定 (37)4.4LAMB的问题 (38)4.5表面波：与边界元的对比 (41)4.6施加在多层系统上的脉冲荷载：与波谱单元比较 (43)5理论 (46)5.1动力特性的基本方程 (46)5.2时间积分 (47)5.2.1波速 (48)5.2.2临界时间步 (48)5.3模型边界 (48)5.3.1吸收边界 (49)5.4初始应力和应力增量 (49)6 参考文献 (51)1 简介土体与结构不仅承受地表建筑物的静荷载，通常还会承受动力荷载。