改性高水材料尺寸与形状效应研究

Experimental Study on the Size and the Shape of High-water-content Material that Modified

改性高水材料是在原高水材料的基础上通过掺杂或改性,以达到提高其物理力学性质和降低经济成本等目的的新型高水材料,近年来在地下采空区充填支护等领域得到了广泛应用。同岩石和混凝土等材料一样,其形状和尺寸对力学性质影响显著,因此对改性高水材料形状和尺寸效应的研究具有重要意义。为研究不同形状和尺寸改性高水材料的力学性质,借助ETM力学试验系统,通过对不同尺寸和形状下的改性高水材料的破坏过程、抗压强度和变形特性等性质的测试,系统研究改性高水材料的尺寸和形状效应。结果表明:改性高水材料是一种弹塑性材料,其变形破坏过程可以分为弹性阶段、屈服阶段、塑形阶段和破坏阶段4个过程;改性高水材料的尺寸仅影响其应力-应变曲线峰值强度,对曲线的形状几乎没有影响,而形状对应力-应变曲线的峰值强度和形状均有较大影响;相对于圆柱体试件,立方体试件的全应力-应变曲线屈服后下降得更加缓慢;随着材料尺寸的增加,圆柱体和立方体试件的抗压强度、弹性模量和变形模量均在一定范围内逐渐减小,且当试件尺寸较小时(小于100mm),尺寸增加25%,弹性模量降低约50%,变形模量约降低10%,尺寸较大时(大于100 mm),变化率急剧减小;在相同条件下,圆柱体试件的抗压强度、弹性模量大于立方体试件,变形模量小于立方体试件。

The modified High-water-content material has been widely served as the filling materials. As a concrete,its size and shape has a distinct impact on the mechanical properties. In order to study the mechanical properties of different shape and size,using the analytic equipment of ETM mechanics system in SCU,the nature of the destruction progress,compressive strength and deformation characteristic in different size and shape of high-water-content material doped the fly ash was tested. The results indicated that high-water-content material is elastic-plastic material,the deformation and failure progress could be divided into 4 stages of plastic stage,shaping stage,yield stage and destruction stage. Size only affected the stress-strain curve of the peak strength,however,the shape had greater impact to the peak strength and shape. The full stress-strain curve of the cube specimen decreased with the yield of the cylinder specimen. In the certain ranges,with the increase in size of the material,elastic modulus,deformation modulus gradually decreased within a certain range,the compressive strength of cylinder specimen was greater than cube specimen,when the specimen size was small( less than 100 mm),the size increased by 25%,the elastic modulus decreased by about 50%,the deformation modulus was reduced by about 10%,the larger size( greater than 100 mm),the rate of change was drastically reduced. Under the same conditions,the elastic modulus and compressive strength of cylindrical specimens was greater than cubic specimens,but deformation modulus was much smaller.