水泥粉煤灰加固有机质土的试验研究
EXPERIMENTAL STUDY ON IMPROVEMENT OF ORGANIC SOIL WITH CEMENT AND FLY-ASH
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摘要: 对于高有机质含量的泻湖相软土,单纯采用水泥不能有效提高该软土的力学性能,因此提出了采用水泥和粉煤灰作为固化剂的加固方法。通过不同水泥掺入量、粉煤灰掺入量和龄期下水泥土的无侧限抗压强度试验,分析了水泥粉煤灰固化土的强度规律和变形规律,探讨了水泥和粉煤灰加固高有机质含量软土的机理。结果表明,粉煤灰对于水泥试块的早期强度影响较小,对后期强度影响较大;粉煤灰最佳掺入量为12％,超过此掺入量水泥土强度反而会降低,粉煤灰水泥土的破坏应变、E50也在粉煤灰掺量为12％时分别达到最低值和最大值。水泥掺加粉煤灰可有效地提高高有机质含量软土的强度。Abstract: The soft soils which contain high organic matters usually lead to a low-strength cement-soil. This paper mainly studies the influence of fly ash as an additive on cement-soil. By comparing the unconfined compressive strength of the cement fly-ash soil mixtures with different cement contents, fly ash content and concreting time, the strength and deformation behavior of the mixtures are analyzed. Moreover, the improving mechanism of the organic soil is discussed. The results show that the unconfined compressive strength of the mixtures changed slightly at the beginning. However, the unconfined compressive strength increased remarkably after concreting. The optimal content of the fly ash was about 12%. At this fly ash content, the failure strain and E50 reached the smallest and maximum value, respectively. If the fly ash content exceeded 12%, the unconfined compressive strength of the mixtures decreased.
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