Based on a large numbers of model / simulation test of the intermittent cracked rock - like samples , fatigue strength , fatigue deformation and crack appear in preexisting cracks tips , the growth of crack , the pattern of crack coalescence are studied / analysed systemically by means of cyclic load and static load , in the course of the model test , the difference between cyclic load and static load of crack appear in preexisting cracks tips , the growth of crack and the pattern of crack coalescence are observed and analysed 在试验过程中，观察并分析了循环加载方式下，预置裂隙端部裂纹萌生、扩展、岩桥贯通模式与静载方式下的差异；探讨了疲劳裂纹萌生、扩展的机理，分析了加载频率、荷载水平对裂隙试样疲劳强度、疲劳变形(总变形和不可逆变形)的影响规律。
So how to transfer scientifically self - balanced test data into top load curve according to its actual working behavior , become the obstacle of its practical application . in accordance with actual forcing behavior and reaction mechanism between pile and soil , the article analyzes the relation between top part and bottom part , load transferring mechanism and difference with other loading way by ansys program . so the reliability of determine bearing capacity by self - balance method has been proved 本文根据自平衡加载方式下桩身的实际受力状况、桩土间的相互作用机理以及单桩破坏机理，建立了单桩的离散元模型，采用ansys通用分析软件，选取合理的单元类型、材料特性等，数值分析了基桩在自平衡加载方式下上下桩段的相互关联、荷载传递机理以及与其它加载方式的区别，论证了采用自平衡试桩法测定单桩极限承载力的可行性。
So it is not enough if we only execute linear analysis to a cable - stayed bridge ; 2 ) when live loads are distributed to full span the effects of geometric nonlinear for the structure are smaller than to two side spans or mid - span only ; 3 ) linear analysis is enough to live loads since the difference between linear analysis and nonlinear analysis to the structure is relatively small under live loads ; 4 ) the effects of every geometric nonlinear element to decision final shape parameters are very little , and the results of linear and nonlinear are nearly equal ; 5 ) under construction the effects of geometric nonlinear to cable - stayed bridges must be considered 2 )活载作用下，加载方式不同，非线性的影响结果也不一样，其中按全桥满布方式进行加载时受几何非线性的影响最小。 3 )活载作用下，可以用线性分析的手段对活载进行近似计算，以便减少计算量。 4 )各非线性因素对结构最终形态确定参数的影响非常小，线性结果与非线性结果相差无几。
