Yao Yafeng, Cheng Hua, Lin Jian, Ji Jingchen
School of Civil Engineering, Nantong Vocational University, Nantong, 226001, China.
Post-Doctoral Research Station of Safety Science and Engineering, Anhui University of Science and Technology, Huainan, 232001, China.
Sci Rep. 2021 Sep 23;11(1):18974. doi: 10.1038/s41598-021-98374-1.
The creep characteristics of frozen rock and soil are crucial for construction safety in cases of underground freezing. Uniaxial compression tests and uniaxial creep tests were performed at temperatures of - 10, - 15, - 20, and - 25 °C for silty clay used in Nantong metro freezing construction to investigate the effect law of the stress-strain curves and creep curves. However, owing to the complex effects of factors such as temperature and ground pressure, the mechanical properties of underground frozen silty clay are uncertain. The Burgers creep damage model was established by using an elastic damage element to simulate the accelerated creep stage. The traditional particle swarm optimization algorithm was improved using the inertia weight and the fuzzy random coefficient. The creep parameters of the Burgers damage model were optimized using the improved fuzzy random particle swarm algorithm at different temperatures and pressure levels. Engineering examples indicated that the optimized creep model can more effectively characterize the creep stages of frozen silty clay in Nantong metro freezing construction. The improved fuzzy random particle swarm algorithm has wider engineering applicability and faster convergence than the traditional algorithm.
冻土和土壤的蠕变特性对于地下冻结情况下的施工安全至关重要。针对南通地铁冻结施工中使用的粉质黏土，在-10、-15、-20和-25℃的温度下进行了单轴压缩试验和单轴蠕变试验，以研究应力-应变曲线和蠕变曲线的影响规律。然而，由于温度和地压等因素的复杂影响，地下冻结粉质黏土的力学性能具有不确定性。通过使用弹性损伤元件模拟加速蠕变阶段，建立了Burgers蠕变损伤模型。利用惯性权重和模糊随机系数对传统粒子群优化算法进行了改进。采用改进的模糊随机粒子群算法，在不同温度和压力水平下对Burgers损伤模型的蠕变参数进行了优化。工程实例表明，优化后的蠕变模型能够更有效地表征南通地铁冻结施工中冻结粉质黏土的蠕变阶段。与传统算法相比，改进的模糊随机粒子群算法具有更广泛的工程适用性和更快的收敛速度。
