Study on the unsteady excavation of submarine soft rock mass

一些挖掘机的开挖机理，如抓斗、翻斗等，主要以不稳定开挖为主，开挖深度随开挖进度而变化。为此，对软岩体进行了不稳定开挖试验，并运用理论或实验方法阐明了软岩体的基本性质。首先根据实验结果分析了切削刃受力与位移之间的关系，并对影响这种关系的几个因素进行了研究。在此基础上对开挖岩体体积进行了评价。利用弹塑性本构方程进行了有限元分析，与试验结果进行了对比，并验证了切削刃附近岩石地面的破坏模式。最后将研究结果应用于一台实际挖掘机，验证了本研究的正确性。研究中主要使用的参数为前倾角、开挖距离、竖向侵彻力和软岩抗剪强度。除抗剪强度外的参数均可由挖掘机的尺寸确定。因此，本研究的主要目标是：(1)根据输入的抗剪强度信息，给出挖掘阻力和刃口轨迹的计算公式；(2)将公式应用于实际挖掘机，验证公式的适用性。

The mechanism of excavation experienced in some excavators, for example grab bucket, clamshell bucket etc, is mainly occupied by unstable excavation, in which the excavating depth is varied with the progress of excavation. Therefore the experiments on the unstable excavation were carried out for soft rock mass and the basic properties were clarified with some theoretical or experimental methods. At first the relationship between the forces applied to cutting edge and the displacements were analysed based on experimental results and several factors affecting the relations were investigated. Then the excavated rock volume was evaluated based on the results of the previous consideration. FEM analysis by use of elasto-plastic constitutive equations were also carried out in order to compare with the experimental results and to check the failure pattern of rock ground in the vicinity of the cutting edge. Finally these research results are applied to a real excavator to check the appropriateness of this study. Parameters mainly used in this study are rake angle, excavating distance, vertical penetration force and shear strength of soft rock. The para-meters except the shear strength can be obtained from the size of the excavator. The main targets of this study were therefore (1) to give formula on excavating resistance and the locus of cutting edge on the basis of the input information about the shear strength, (2) to check the appropriateness of the formula by applying them to a real excavator.