麦秸秆加筋盐渍土的尺寸效应与制样问题处置

制备均匀且整体性较好的试样是保证室内实验结果可靠的前提条件。提出了两端压实的静力制样法,围绕制样中出现的几个问题,制定了适宜的应对措施。同时完成了不同直径的盐渍土和麦秸秆加筋土试样的抗压强度实验,分析了试样抗压强度的尺寸效应,以及试样直径与加筋条件间的比例关系。结果显示:采用两端压实的静力制样方法制备加筋土试样是可行的;两种试样均存在明显的尺寸效应;由于麦秸秆的加筋作用,使得麦秸秆加筋土不同尺寸试样的抗压强度尺寸效应大于盐渍土的,且其抗压强度的尺寸效应随试样尺寸的增大而越来越明显;适宜加筋长度为0.316倍试样直径,适宜加筋率0.25%。研究结果可为制备合格的加筋土试样提供参考,也有益于在未来的研究中选择更合理的麦秸秆加筋条件。

Size effect in mechanical experiments of reinforced saline soil with wheat straw and preparation for specimen

Preparing uniform and well specimen is a basic requirement for obtaining reliable results in laboratory test.The specimen-preparing method with double-end static pressure is proposed and the corre-sponding problems in the stage are involved in this paper.At the same time,the unconfined compressive strength of saline soil and reinforced soil with wheat straw in different size is testified.The results,size effect of compressive strength and the relation between optimum reinforced condition and sample＇s diame-ter,show that： Improved doubleend static pressure method is feasible in preparing samples of reinforced soil.Size effect exists in both of saline soil and reinforced soil.Size effect of reinforced soil in different size is more than that of saline soil because of the reinforcement action of wheat straw,and it is more obvious with an increase of the sample dimension for reinforced soil.Desirable reinforcement length is of 0.316 times sample diameter,while desirable reinforcement ratio is 0.25%.The results can provide a guide to obtain a more uniform and well specimen for reinforced soil,and is benefit to select more reasonable reinforced condition in the further study.