
冻融循环条件下玄武岩耐久性研究
李博文, 荣冠, 蒙世仟, 吴琦, 全军松
冻融循环条件下玄武岩耐久性研究
The Durability of Basalt under Freeze-thaw Cycles
通过试验研究了隐晶质玄武岩在不同冻融循环次数下的物理力学特性变化规律与变形破坏特点,并采用Mutlutűk等提出的衰减模型分析了岩石的冻融耐久性。研究发现:冻融作用下玄武岩力学性能显著下降,岩石的损伤劣化主要发生在前20次冻融循环过程中,随着冻融次数继续增加损伤劣化作用减弱。最终在30次冻融后强度、弹性模量分别降低了44.9%、23.2%;通过试验结果统计分析得到了各物理力学指标随冻融次数的拟合关系式;在冻融作用下玄武岩的强度与特征应力等指标具有较好一致性,其敏感性参数(半衰期)数值也较接近,适用于岩石冻融耐久性分析。
Freeze-thaw cycle tests on basalt are carried out to study the change of the physical and mechanical properties and the characteristics of characteristics. The durability of physical and mechanical indexes of rock under freeze-thaw cycles is analyzed by attenuation model. The results show that ① the mechanical properties of basalt decrease significantly under the freeze-thaw cycles. The damage deterioration of the rock mainly occurs during the first 20 freeze-thaw cycles, and the damage deterioration weakens as the number of freeze-thaw cycles continue to increase. ② The fitted relationship equation of each physical and mechanical index with the number of freeze-thawing is obtained by statistical analysis of the test results. ③ The strength and characteristic stresses of basalt under freeze-thawing are in good agreement, and the values of their sensitivity parameters are also close, which are suitable for rock freeze-thawing durability analysis.
冻融循环 / 耐久性 / 隐晶质玄武岩 / 负指数模型 {{custom_keyword}} /
freeze-thaw cycles / durability / cryptocrystalline basalt / negative exponential function model {{custom_keyword}} /
表1 隐晶质玄武岩物理参数Tab.1 Physical parameters of cryptocrystalline basalt sample |
干密度ρd /(g·cm-3) | 饱和密度ρs /(g·cm-3) | 孔隙率/% | 饱和吸水率/% | 纵波波速/(m·s-1) |
---|---|---|---|---|
2.83 | 2.86 | 2.96 | 1.05 | 4 412 |
表2 玄武岩物理与力学参数随冻融循环次数的变化Tab.2 The variation of basalt physical and mechanical parameters with freeze-thaw cycles |
冻融循环/次 | 饱和密度/(g·cm-3) | 波速/(m·s-1) | 单轴抗压强度/MPa | 弹性模量/GPa | 起裂应力/MPa | 损伤应力/MPa | 泊松比 | 峰值应变/% |
---|---|---|---|---|---|---|---|---|
0 | 2.860 10 | 4 412 | 190.20 | 45.03 | 93.76 | 172.46 | 0.253 | 0.439 |
10 | 2.860 36 | 4 292 | 143.98 | 40.36 | 68.35 | 122.81 | 0.361 | 0.360 |
20 | 2.860 46 | 4 258 | 119.87 | 36.03 | 37.47 | 83.26 | 0.210 | 0.355 |
30 | 2.860 51 | 4 143 | 104.81 | 34.59 | 36.57 | 75.83 | 0.219 | 0.294 |
表3 不同冻融次数下玄武岩的损伤变量与冻融系数Tab.3 The damage variable and freeze-thaw coefficient of basalt with different freeze-thaw times |
冻融循环次数 | 损伤变量(D) | 冻融系数(Kfm ) |
---|---|---|
0 | 0 | 1.000 00 |
10 | 0.103 72 | 0.756 98 |
20 | 0.200 00 | 0.630 21 |
30 | 0.231 96 | 0.551 06 |
表4 冻融作用下玄武岩物理力学指标的衰减常数与半衰期Tab.4 The attenuation constant and half-life period of physical and mechanical indexes under freeze-thaw cycles |
物理力学指标 | 衰减常数λ | 半衰期N 1/2/次 |
---|---|---|
单轴抗压强度(σc ) | 0.020 93 | 33.1 |
弹性模量(E) | 0.009 29 | 74.6 |
起裂应力(σci ) | 0.036 61 | 18.9 |
损伤应力(σcd ) | 0.030 98 | 22.4 |
波速(Vp-wave ) | 0.001 97 | 351.9 |
冻融系数(Kfm ) | 0.020 92 | 33.1 |
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