边坡稳定性评价MSARMA法及最佳加固力研究

Study on the MSARMA method for evaluating the slope stability and the optimum reinforcement force

目前,各行业在边坡稳定性评价和设计中采用的方法主要是极限平衡方法。文章对各种极限平衡方法的特点和适用范围进行了综合评价,在此基础上,提出了适用于岩质高边坡稳定性评价和设计的一种极限平衡方法———MSARMA法和基于该方法开发研制的"边坡工程稳定性MSARMA法评价分析系统"。该方法是在著名的SARMA法基础上改进形成的,同其它极限平衡方法比较,具有推导严格、假设条件较少、实用性强等优点。此系统不仅能够进行在非齐次边界条件下的稳定性计算,而且还能够进行坡面存在荷载和加固力情况下的边坡稳定性计算。鉴于目前边坡工程规模愈来愈大的特点,提出了边坡最佳加固力概念,此概念认为,对于边坡加固工程,应综合考虑各种状态下的边坡稳态,寻找导致边坡失稳最不利因素的组合状态,加固力的大小只要保证边坡在该状态下稳定就行,此时的加固力就是最佳加固力。考虑到岩土工程的复杂性、计算所采用的力学模型、物理力学性质参数等具有的非绝对准确性和确定性,在设计时应在最佳加固力基础上,再增加一定的保险系数,但该保险系数不宜过大,实施时应根据具体工程规模确定,一般应在0 05以内。此时对边坡进行加固既满足边坡的稳定性要求又经济合理。以实际工程为例,展示了MSARMA法广阔的应用前景。

At present, the limiting equilibrium method is always adopted for the evaluation and design of slope stability in various industries. Firstly, the paper makes a comprehensive evaluation to the characteristics and application slope of various limiting equilibrium methods, and based on this, the paper puts forward a limiting equilibrium method-MSARMA method and the 'MSARMA analysis and evaluation system of slope stability' based on the MSARMA method. The method is formed through modifying the famous SARMA method; in comparison with other limiting equilibrium methods, it has such advantages as the strict deductions, few presumptions and strong practicability. The software system cannot only solve the stability calculation under the inhomogeneous boundary conditions, but also do the stability calculations under the conditions that there are loads and reinforcement forces on the slope surface. Considering the scale of the slope engineering is becoming larger and larger, this paper puts forward the concept of optimum reinforcement force, which indicates that in a slope reinforcing engineering, the stable states of slope under different conditions shall all be taken into account to find out the assemblage state of the most unfavorable factors, and that the size of the reinforcement force shall ensure the stability of slope under such condition, and the reinforcement force at this point is the optimum force. As regards the complexity of geotechnical engineering, the non-absolute exactness and determinacy of the mechanical models and physical-mechanical parameters, a certain safety coefficient shall be added to the optimum reinforcement force during the design, but the safety coefficient shall be too large, which shall be determined according to the scale of the concrete project, as a general rule, it shall be within 0.05. Such reinforcement to the slope does not only meet stability requirements, but also are economical and reasonable. An engineering case is given in this paper to show the wide application prospect of the MSARMA method.