混凝土材料剪切强度的试验研究

Experimental study on shear strength of concrete

目前在水利、岩土、隧道、石油等工程中混凝土材料处于塑性状态,需要按弹塑性理论来分析计算,因此必须知道衬砌混凝土材料的剪切强度参数,即黏聚力c与内摩擦角φ,但目前国内尚无确定的统一方法和标准。借鉴岩土抗剪强度试验原理,在现有试验设备条件下,提出将直剪试验与单轴抗压试验相结合的方法来测试混凝土的剪切强度。通过对不同强度等级混凝土进行室内试验,得到相应强度等级混凝土剪切强度指标c、φ值,同时利用理论公式和有限元超载法对不同等级混凝土剪切强度进行理论与数值验证,结果表明本研究提出的抗剪强度试验方法与剪切强度指标是基本准确可靠的。

Concrete in the state of plasticity is needed to analyze by elastic - plastic theory for large engineering project,such as：water conservancy project,tunnel engineering,geotechnical engineering,petroleum engineering,so the shear strength parameters of lining con-crete,i.e.cohesion c and internal friction angel φ,have to be known in the design calculation of cavern lining,but there is no unified method and standard so far.Based on the experimental principle of shear strength for geomaterials,a new method combining the direct shear test and uniaxial compression test is put forward to measure the shear strength of concrete under the existing limit conditions.The shear strength indexes of concrete with different strength grade are obtained through laboratory tests.Theoretical analysis and numerical simulation,including excess load method,validate this method′s feasibility and results′reliability.