地质力学模型试验方法与变温相似模型材料研究

STUDY OF TEST METHOD OF GEOMECHANICAL MODEL AND TEMPERATURE ANALOGOUS MODEL MATERIAL

研究新型地质力学模型材料是研究高坝和地基稳定物理模拟的关键技术问题之一,对高坝建设具有重要理论意义和工程应用价值。介绍地质力学模型试验新型模型材料——变温相似材料和试验方法,推导超载法、强度储备法和综合法的安全度公式,并阐述其物理意义。材料试验研究结果表明,变温相似材料的抗剪断强度τm、黏聚力cm和摩擦因数fm等力学指标随着温度的升高而逐步降低,与温度变化成反比关系;在模型试验中通过升高模型材料温度的方式来降低材料的力学指标,从而能在一个模型上实现强度储备法和综合试验法;温度场对试验变位结果影响约为6%,对应力结果影响为-6%～9%,且温度变化越小,其影响程度越小。该材料及其试验新技术已成功应用于锦屏一级和大岗山等高拱坝的地质力学模型试验,具有良好的应用价值和工程实用意义。

Study of new geomechanical model material is one of key problems for physical modeling stability of high dam, which has not only theoretical significances, but also has value for engineering application. A new model material for geomechanical model test, temperature analogous material, is introduced and computing formulas of stability margin for overloading method, strength reserve method and comprehensive method are derived. It is shown from test findings that shearing strength ιm as well as cohesion cm and internal friction coefficient fm of temperature analogous material will decreases as the temperature increases. By reducing mechanical index of material with increasing material temperature in model test, both strength reserve method and comprehensive method can be realized in the same model. At the same time, studies show that temperature field has influence on deformation within 6% range and on stress within range from -6% to 9%; and the lower temperature slightly changes, the less influence degree is. Such material and its new testing technique have been successfully adopted in geomechanical model test for high arch dams such as Jinping I, Dagangshan, etc. and are significantly valuable to engineering application