基于响应面法的复合改良膨胀土无侧限抗压强度研究

为提高膨胀土的无侧限抗压强度,降低工程危害。本文在木质素改良膨胀土的研究基础上,通过单因素试验研究纤维长度、纤维掺量及木质素掺量对膨胀土抗压强度的影响规律,基于单因素试验结果,通过BBD响应面设计法进行响应面试验,建立二次回归模型,研究了双因素作用下对膨胀土无侧限抗压强度的影响。结果表明:单因素作用时,膨胀土无侧限抗压强度在各因素下均呈现先增大后减小的趋势;双因素交互作用时,木质素掺量和聚丙烯掺量二者交互作用显著性最好。由BBD响应面法得到的最优组合为:聚丙烯纤维长度为9 mm、纤维掺量为0.3%、木质素掺量为3%,该变量下平行试验组的平均抗压强度为552.48 kPa,相比于素膨胀的抗压强度提升了76.97%。可见此方案下对素膨胀的抗压强度提升效果最好。

Study on Unconfined Compressive Strength of Composite Improved Expansive Soil Based on Response Surface Method

In order to improve the unconfined compressive strength of expansive soil and reduce engineering hazards. Based on the research of lignin-improved expansive soil, the influence of fiber length, fiber content and lignin content on the compressive strength of expansive soil was studied through univariate experiments, and based on the results of single-factor tests, the response surface test was carried out by BBD response surface design method, and a quadratic regression model was established, and the influence of two-factor action on the unconfined compressive strength of expansive soil was studied. The results show that under the univariate action, the unconfined compressive strength of expansive soil shows a trend of first increasing and then decreasing under all factors. When the two-factor interaction occurs, the interaction between lignin content and polypropylene content is the most significant. The optimal combination obtained by the BBD response surface method was as follows: polypropylene fiber length was 9 mm, fiber content was 0.3%, lignin content was 3%, and the average compressive strength of the parallel test group was 552.48 kPa, which was increased by 76.97% compared with the compressive strength of prime expansion. It can be seen that the compressive strength improvement effect of prime expansion is the best under this scheme.[ ]