大尺寸富水卵砾石样冻结状态下的力学特性

Mechanical Properties of Large-size Water-rich Gravel Samples in Frozen State

为了探究大尺寸富水卵砾石样冻结状态下单轴抗压强度与冻结温度的关系,以南宁市地铁1号线民族大学-青川站区间联络通道富水卵砾石样为研究对象,自研大尺寸模具制备试样,通过GCTS试验平台对试样进行单轴抗压试验,探究试样强度与冻结温度的相互作用关系。试验结果表明:试样抗压强度随着冻结温度的降低不断增加,试样承载能力不断增强,由2.18 MPa增长到3.1 MPa,试验轴应变随着冻结温度的降低不断减小;冻结状态下,卵砾石试样强度主要受冰的强度、冰卵砾石连接强度以及试样中未冻水含量的影响,在一定范围内,降低冻结温度冰强度增强、冰卵砾石连接强度增强、未冻水含量减小,黏聚力提高,内摩擦角略微增大,造成卵砾石试样随着冻结温度的降低强度不断增强;卵砾石试样达到最大抗压强度时轴应变随着冻结温度的降低不断减小,由7.4%降低到3.2%,表明试样随着冻结温度的降低,脆性增强延性减弱,试样破坏趋向于脆性破坏。

To explore the relationship between the uniaxial compression strength and the freezing temperature of the large size and rich water and egg gravel like frozen state,this paper took the water rich egg gravel sample of the liaison channel of the National University of Nanning and Qingchuan station as the research object,then produced the large size mold preparation sample,and carried out the single axis resistance to the sample through the GCTS test platform.The interaction relationship between the strength of the specimen and the freezing temperature was tested.The test results show that the compressive strength of the sample increases with the freezing temperature decrease,the bearing capacity of the sample increases continuously from 2.18 MPa to 3.1 MPa,and the strain of the test axis decreases with the freezing temperature decrease;under the freezing condition,the strength of the egg gravel test sample is mainly influenced by the strength of ice,the strength of the connection of the ice and gravel,and the content of the unfrozen water in the sample.In a certain range,the strength of the freezing temperature,the strength of the ice and gravel connection,the decrease of the content of the unfrozen water,the cohesive force and the internal friction angle increase slightly,and the gravel specimen will be frozen with the freezing temperature.The tensile strength of the specimen increases continuously,and the axial strain decreases with the freezing temperature decrease,from 7.4%to 3.2%when the maximum compressive strength is reached,indicating that the brittle ductility decreases with the decrease of the freezing temperature,and the failure of the specimen tends to brittle failure.