中文摘要：

中性点理论是地下工程锚固理论中的重要理论，但目前对于中性点位置的确定计算公式存在不合理之处。在前人工作的基础上，对中性点理论进行了完善和改进。在建立的锚杆解析本构模型的基础上，结合中性点理论中锚杆中性点位置处的摩阻力为0的思想，对影响中性点位置的因素进行了较详细的分析，得出了影响锚杆中性点位置的相关因素。通过分析研究得到，静水垂直主应力、锚杆长度、锚杆行间距等3个因素对锚杆中性点的位置没有影响，而洞室半径、岩体弹性模量、锚杆弹性模量、锚杆直径等4个因素对其有显著的影响。其中，洞室半径、锚杆直径与中性点位置基本呈线性函数关系，而岩体弹性模量、锚杆弹性模量与中性点位置呈指数函数关系，岩体弹性模量与中性点位置呈递减指数函数关系，锚杆弹性模量与中性点位置呈递增指数函数关系。通过对这些因素的分析，得出了锚杆中性点位置与相关参数之间的统一函数关系，为进一步研究中性点理论提供了一定的参考意义。

英文摘要：

The neutral point theory is the important theory in underground engineering reinforcement theory. At present, the formula to determine neutral point position has been existed some unreasonable place. The neutral point theory had been further consummated and improved on the foundation of pre-researchers. Base on the developed analytical model and the theory of frictional resistance is zero at the neutral point, the factors have been detailed analyzed for affecting the neutral point position; and the correlations have been gained which affecting neutral point position. Through analyzing, it is revealed that the hydrostatic primary stress, bolt length, bolt spacing having no influence to neutral point position, and the radius of tunnel, Young＇s moduli of rock and bolt, the bolt diameter having remarkable influence to it. Among them, it is linear relation among the radius of tunnel, the bolt diameter with the neutral point position, but it is exponential function relations among the Young＇s modulus of rock and bolt with the neutral point position. The relationship of Young＇s modulus of rock mass and neutral point position presents exponential decreasing; the relationship of Young＇s modulus of bolt and neutral point position presents exponential increasing. Through the factors analyzed, it has obtained that the general functional between the neutral point position and the correlation parameter, for further to study the neutral point theory providing the certain reference significance.