赵涛 杨更社 任俊童 韩力 贾海梁

摘 要：寒区工程普遍面临低温带来的各种工程灾害问题，其中岩土体冻结后强度特性的变化是核心诱因之一。岩土体冻结后强度提高，有利于岩土体的稳定。但在其解冻过程中强度会发生显著弱化，可能会引发工程灾害，因此必须研究不同负温下冻结岩石的力学特性。对常温（20 ℃）及不同负温条件下（-2，-4，-6，-8，-10，-12，-15，-20 ℃）砂岩的抗压强度和抗拉强度特性进行测试。研究结果表明：冻结温度低于-10 ℃時，岩石主要出现脆性破坏;冻结温度高于-10 ℃时，岩石以塑-弹性破坏为主。冻结温度对抗拉强度和抗压强度均有显著影响，冻结温度越低，强度越大，-20 ℃时抗压强度是常温下的3倍，抗拉强度是常温下的4.8倍。不同温度范围内，抗拉强度和抗拉强度随温度的变化速率不同，-2～0 ℃时其变化速率均达到最大值，抗压强度变化速率为6 MPa/℃，抗拉强度变化速率为0.6 MPa/℃.冻结温度越低，弹性模量越大，0～-8 ℃时弹性模量变化速率为1.125 MPa/℃，-10～-20℃时变化速率为0.15 MPa/℃.综上分析，不同冻结温度下孔隙冰和未冻水的含量不同，导致不同温度下岩石抗压强度和抗拉强度差异巨大。关键词：砂岩;冻结温度;单轴抗压强度;抗拉强度;中图分类号：TU 458

文献标志码：A

文章编号：1672-9315（2020）06-0996-07

DOI：10.13800/j.cnki.xakjdxxb.2020.0609开放科学（资源服务）标识码（OSID）：

Influence of temperatures on the mechanical properties

of frozen saturated sandstone

ZHAO Tao，YANG Geng-she，REN Jun-tong，HAN Li，JIA Hai-liang

（College of Civil and Architectural  Engineering，Xian University of Science and Technology，Xian 710054，China）Abstract：

There often occur engineering disasters in cold area projects due to

by low temperature，and one of the core causes is the change of strength characteristics after rock and soil

freeze.Freezing strengthens saturated porous rocks which increases the stability of rock mass，on the other hand，thawing will significantly weaken frozen rocks and may well cause engineering disasters.In this paper，the compressive strength and resistance of sandstone under different temperature conditions（20，-2，-4，-6，-8，-10，-12，-15，-20 ℃） was tested as well as tensile strength.The results show that：when the freezing temperature is lower than -10 ℃，the rock mainly exhibits brittle failure;when the freezing temperature is higher than -10 ℃，the rock is mainly plastic-elastic failure.The freezing temperature has a significant effect on tensile strength and compressive strength.The lower the freezing temperature，the higher the strength.The compressive strength at -20 ℃ is three times that at normal temperature，and the tensile strength is 4.8 times at normal temperature.The tensile strength and tensile strength vary with temperature in different temperature ranges.The rates of both strength change reach the maximum at -2～0 ℃，0.6 MPa/℃ and 6 MPa/℃ respectively.The lower the freezing temperature，the larger the elastic modulus.The rate of change of elastic modulus at 0～-8 ℃ is 1.125 MPa/℃，and the rate of change at -10～-20 ℃ is 0.15 MPa/℃.In summary，the content of pore ice and unfrozen water at different freezing temperatures is different，resulting in a large difference in compressive strength and tensile strength of rock at different temperatures.Key words：sandstone;freezing temperature;uniaxial compressive strength;tensile strength

0 引 言

中国寒区分布广泛，主要集中在西北和东北地区。随着“一带一路”倡议及“西部大开发”战略的持续推进，越来越多的寒区工程将要在一带一路沿线地区开展，高寒地区工程活动必然会面对冻结岩石的强度特性问题[1-2]。……