纤维丝和网加筋泡沫轻质土力学特性和抗冻性

为分析短纤维丝和纤维网加筋对泡沫轻质土力学性能和抗冻性的影响，开展了一系列的无侧限抗压强度试验、抗折强度试验、动三轴试验和冻融循环试验.试验结果表明：对提高抗压强度而言，设计湿密度为700 kg/m³的泡沫轻质土掺入短纤维丝的最优长度和掺量分别为6 mm和0.4%；采用长度6 mm和掺量0.4%的短纤维丝对设计湿密度在400～1 000 kg/m³的泡沫轻质土进行加筋后，泡沫轻质土抗压强度、抗折强度和动应力阈值得到了显著地提高，最小提高量分别为35.3%、31.4%和53.4%；采用长度6 mm和掺量0.6%的短纤维丝对泡沫轻质土进行加筋后，设计湿密度分别为400、700、1 000 kg/m³的泡沫轻质土抗冻融循环次数分别由5、25、125次提高至10、50次和超过150次，泡沫轻质土抗冻性得到了显著地提高；相对于提高泡沫轻质土抗折强度而言，纤维网0.4%短纤维丝复合加筋的效果最好，单一纤维网加筋方式次之，单一短纤维丝加筋方式最差；短纤维丝、纤维网或两者复合加筋均显著地增加泡沫轻质土的韧性.

Mechanical Property and Frost Resistance Analysis of Foamed Lightweight Soil with Fiber Filament and Mesh Reinforcement

In order to analyze the influence of the short fiber filaments and fiber mesh reinforcement on the mechanical property and frost resistance of foamed lightweight soil, a series of tests including unconfined compression tests, flexural strength tests, dynamic triaxial tests, and freeze-thaw cycle tests were performed. The results showed that to improve the compressive strength of the foamed lightweight soil, the optimal length and content of the short glass fiber mixed into the foamed lightweight soil with a design wet density of 700 kg/m3 are 6 mm and 0.4%, respectively. After the foamed lightweight soil with the designed wet density ranging from 400 to 1 000 kg/m3 was reinforced using short glass fibers with length of 6 mm and content of 0.6%, their compressive strength, flexural strength, and dynamic stress threshold were significantly improved, with the minimum increases being 35.3%, 31.4% and 53.4%, respectively. When the foamed lightweight soil had been reinforced with short glass fibers with length of 6 mm and content of 0.6%, the freezing-thawing durability of the foamed lightweight soil with design wet densities of 400, 700 and 1 000 kg/m3 increased from 5 cycles to 10 cycles, 25 cycles to 50 cycles, and 125 cycles to more than 150 cycles, respectively. This indicates that the frost resistance of the foamed lightweight soil was significantly improved. To improve the flexural strength of the foamed lightweight soil, the effect of the reinforcement by the glass fiber mesh combined with short fiber filaments (0.4% in weight) was the best, the effect of the single glass fiber mesh reinforcement was the second, and the effect of the single glass fiber filament reinforcement was the worst. Additionally, the toughness of the foamed lightweight soil can be improved significantly by short glass fiber filament reinforcement, glass fiber mesh reinforcement, or glass fiber mesh combined with short glass fiber filament reinforcement.