Still , the change of vg parameter in the beam was investigated in this thesis . dilation of plastic belt in the beam is also studied . analysis show that there is clear direction during the dilation of plastic belt , which is similar with the path of shear - mode fracture 分析表明塑性区的扩展有明显方向性，据此得到的塑性区扩展方向与剪切型断裂时的断裂路径比较接近，也与加载过程中韧带区出现的集中剪切滑移线的方向比较一致。
The effects of the mechan cal parameters of the sunounding rock and mechanical model on the plastic region , stress and displacement are discussed the rationalities on chambers ' parameters , supporting patterns and relative supporting parameters of underground powerhouses are verified 探讨了围岩力学参数以及围岩力学模型对洞周塑性区、应力与位移的影响，通过多种方案计算和比较，论证了向家坝地下厂房大型洞室参数、支护形式、支护参数的合理性。
In this arithmetic , the objective function is modified gradually by distinguishing the rigid zone and plastic zone before carry through more calculation , in order to obtain the optimal solution of the programs . the convergence of the algorithm is also shown in this paper 基于最优化理论及其求解方法，提出了一种求解塑性极限载荷的直接迭代算法，通过逐步识别刚性区和塑性区，不断修正目标函数，以逐步求得问题的最优解，论文证明了该优化算法的收敛性。
Non linear static & dynamic finite element procedure is adopted for the true emulation of the four typical geologic profiles of the dam , and imitates to compute the each stage deformation and stress distribution from the dam fill to full water run and during the 7 degree seismic intensity , the article also imitates to compute the response to earthquake force , the excess vibration pore water pressure distribution and permanent deformation , predicting the occurrence possibility of the crac ^ plastic zone and earthquake liquefaction 采用非线性静、动力有限元分析程序对围坝的4个典型剖面进行了静、动力仿真模拟，模拟计算了坝体自填筑至蓄水运行和发生7地震各阶段坝体及坝基的变形以及应力分布，地震应力响应和地震引起的超静振动孔隙水压力分布以及永久变形。判断了坝体和坝基中出现裂缝、塑性区以及地震液化的可能性。
In the calculations of ultimate bearing capacity , the section of rc beam was divided into the elastic zone and the plastic zone based on the fire temperature field of the beam ' s section , the equivalent - floor - live - load was presented to describe the weakening of the bearing capacity of structure members in fire , the correlation expressions were established 摘要根据梁截面火灾温度场，将梁截面混凝土分为弹性区和塑性区2部分计算火灾场梁极限承载力，并采用等效楼面活荷载描述火灾场高温对梁极限承载力的削弱，推导了相关的计算公式。
Then a dynamic visualization software - - afterdraw , which aims at 2d elastic - plastic fem , is programmed . afterdraw is capable of drawing the deformation figures of material , the regions of plasticity and the regions of tension distributing figures , primary stress vector figures and primary strain vector figures . besides , atterdraw could realistically dynamically simulate the deformation of the whole process of construction 在此基础上，研究了针对二维弹塑性有限元的动态可视化后处理软件afterdraw ， afterdraw能够绘制基坑工程各步施工的结构变形图、塑性区和受拉破坏区分布图、主应力矢量图和位移矢量图， afterdraw还能够逼真地动念模拟基坑工程整个施工过程变形情况。
Using the complex potential method in the plane theory of elasticity of an anisotropic body , a series solution to the stress field of a finite plate containing multiple cracks subjected to arbitrary loads is obtained by means of the faber series expansion , and the stress intensity factors at the crack tips are calculated based on the theories of fracture mechanics . equivalence yield stress is introduced in order to consider the effects of the plastic zones , with which the strip yield criteria is developed in the article so that the effects of structural size and the crack interactions on the stress distribution can be considered accurately . the effects of plate size , crack size and crack distributions on the stress intensity factors as well as the residual strength of the plate are studied detailedly 采用各向异性体平面弹性理论中的复势方法，以faber级数为工具，得到了含多裂纹有限大板在任意载荷作用下应力场的级数解，并应用断裂力学方法确定裂纹尖端的应力强度因子；引入当量屈服应力考虑裂尖塑性区的影响，提出基于带屈服准则的剩余强度分析模型，能够充分考虑结构尺寸和裂纹之间相互作用对应力场的影响；通过数值计算详细讨论了结构尺寸和裂纹之间位置关系对应力强度因子和结构剩余强度的影响规律，得到了一系列对工程应用具有实用价值的结论。
After excavation , there are concentration phenomenon of stress at the corner or the shiplock room , and the tension zone lies in half of the middle part as well as the part of the two slopes to the lower part of the upright wall . finally the analysis results are compared with site monitoring data in period of construction as well as the feedback reports , the result of all comes to meet with each other very well 开挖完成后，在闸室拐角处存在不同程度的应力集中现象，中隔墩上部1 2的岩体及南北边坡至直立墙顶部平台以下的部分岩体为拉应力区。在两侧边坡及边墙的塑性区出现在损伤区和部分卸荷影响区内，中隔墩大部分区域的岩体都进入了塑性状态，闸室底板处的塑性区基本上与损伤区一致。
According to roof safety factor of 1 . 2 for the mined - out area , minimum safety roof thickness at different rock in various span mined - out area was calculated by flac software , which transfixion of plastic zone was taken as criteria of roof breakage by using strength reduction technology and dichotomy theory 摘要利用强度折减技术和二分法原理，以塑性区的贯通作为顶板破坏的标准，当采空区顶板的安全系数等于1 . 2时，利用flac软件计算得出各种跨度空区在不同岩层中的最小安全顶板厚度。
Researching on the technology if reverse order is to study strains if pits , structural systems if basement , environmental surwey and underpinnings . on account of emphasizing developing methods if checking strength if pick - ets , modemizing machenes of excavation and studying methods of underpinning is put forward and is a way if controlling the quality of pickets in sites , which leads an active effect ; synthetic application if rankintheory , spatial and time effect theory to excavation tl aanalyze the state of soil force and strain is brought forward and the time effect should be considered in the zone of clay , the formation and development of soil plasticity are analyzed and the most dangerous zone to decide how to excavate and where to begin is found ; analyzing the cause of picket settlement during reverse order and the differential settlement and discussing hlw to solute it . duringh the temporary survey and the environmental warship , bringing rorward the theory of environmental vibration and analyzing the state of soil force and probability of losing stabilization of soil under the effect of environmental vibration ; analyzing the state offeree in underground concrete wall by the method of mathematics and pointing out the place of the maximum force and deformation . based on systematic illustrating the reverse order , problems about application and development of reverse order and suggestions also are expressed 鉴于国内外的研究把重点放在大力发展工程桩的实验室承载力监测方法与设备、如何使土方开挖机械现代化及对周围建筑的临测方法上，本文提出了现场利用声波层析成像技术监测钢砼桩内部质量的方法与程序，并得出了声波层析成像技术是砼桩的动态质量检测的有效手段，这对指导施有积极、现实意义；提出了综合运用朗肯土压力理论、基坑空间和时间效应影响理论来分析逆作法施工过程中基坑边坡土体应力及应变的变化情况，指出粘土地区也应考虑时间效应，并且进一步分析了基坑边坡土体的塑性区形成和发展，找出边坡最不利的区域，以确定地下室土体的挖掘的方式和顺序，指出凭主观臆断与经验来施工是不可取的；在分析、经较逆作法与大开挖顺作法的地下室结构体系受力情况及施工顺序的不同，提出了节点处理技术；分析了逆作法施工期间桩的沉降变化原因及由此而产生的差异，并探讨了解决的方法；本文还提出了环境振动对土体边坡稳定产生影响的观点，并分析了在环境振动影响下，土体的应力状态及土休失稳破坏概率，并且还运用弹性力学知识和数学分析的方法定量地分析了地下混凝土墙受力状态，指出了被监测墙体的最大应力、应变位置。
