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基于室内实验研究了人工冻土(重塑粉质黏土)在三点式和四点式两种加载方式下加载速率对抗折强度的影响规律。结果表明:两种加载方式下,破坏类型均呈明显的脆性破坏特征,加载速率对破坏特征几乎无影响。三点式加载方式下,抗折强度与跨中最大相对挠度均随加载速率的增大而呈线性增大趋势,试验范围内(加载速率30~75 N/s),加载速率提高1 N/s,强度增大0.023 MPa,跨中最大相对挠度增大0.038;而四点式加载方式下加载速率对抗折强度及试件破坏时跨中最大相对挠度均无影响。仅从研究人工冻土抗折强度基本特性出发,采用四点式加载方式确定其抗折强度更为合理。
The influence of loading rate on the flexural strength of artificial frozen soils (remolded silty clay) under three kinds of loadings and four loadings was studied based on laboratory experiments. The results show that under both loading methods, the failure types show obvious brittle failure characteristics, and the loading rate has almost no effect on the failure characteristics. Under the three-point loading method, the flexural strength and the maximum relative deflection in the mid-span both linearly increase with the increase of loading rate. The loading rate increases by 1 N / s within the experimental range (loading rate 30-75 N / s) The strength increases 0.023 MPa, and the maximum relative deflection in the cross increases by 0.038. However, the loading rate under four-point loading has no effect on the flexural strength and the maximum relative deflection of the span during specimen failure. Only from the study of the basic properties of artificial permafrost flexural strength, four-point loading method to determine the flexural strength more reasonable.