Triaxial test study of geogrid reinforced sand

Journal Information

J. Hefei Univ. Tech. (Nat. Sci.), Jan.2024, Vol.47 No.1: 83-90

DOI: 10.3969/j.issn.1003-5060.2024.01.013

Authors

WU Liming $ ^{1} $, ZHU Yalin $ ^{1,2} $, XU Qian $ ^{1} $, CHEN Qing $ ^{1,2} $, WANG Yixian $ ^{1,2} $

(1. School of Civil and Hydraulic Engineering, Hefei University of Technology, Hefei 230009, China; 2. Anhui Key Laboratory of Civil Engineering Structures and Materials, Hefei 230009, China)

Abstract and Keywords

Abstract: In order to explore the reinforcement mechanism of geogrids, three geogrids of different mesh sizes were designed. The strain-controlled triaxial instrument was used to carry out the unconsolidated undrained triaxial shear test of reinforced sand. The effects of mesh size of geogrid, number of reinforced layers and confining pressure on the strength characteristics of the sand were investigated. The test results show that when there is no reinforcement, the sand is mainly manifested as the bulging failure of the middle and upper parts. With the increase of the number of reinforced layers, the destructive forms of the sand are successively transformed into the middle bulging failure and shear failure. The partial stress-axial strain curve of plain sand and reinforced sand is characterized by strain softening. Geogrids of different mesh sizes have different effects on the strength characteristics of the sand, and when the mesh size of geogrid is $ 3 \, mm \times 3 \, mm $, the reinforcement effect is similar to that of hardened geotextiles; when the first layer of geogrid is reinforced, as the mesh size of geogrid decreases, it has little effect on the strength of the sand. When the second and third layers of geogrid are reinforced, the smaller the mesh size, the better the reinforcement effect. Adding a geogrid to the sand can effectively increase the cohesion of the sand, and when the mesh size of geogrid is small, the geogrid can also improve the internal friction angle of the sand.

Keywords: geogrid reinforcement; mesh size; strength characteristics; failure morphology; triaxial test

作者信息

吴黎明 $ ^{1} $，朱亚林 $ ^{1,2} $，许倩 $ ^{1} $，陈清 $ ^{1,2} $，汪亦显 $ ^{1,2} $

(1. 合肥工业大学土木与水利工程学院，安徽合肥 230009；2. 土木工程结构与材料安徽省重点实验室，安徽合肥 230009)

摘要和关键词

摘要: 为研究土工格栅的加筋机理,文章设计了3种不同网格尺寸的土工格栅,采用应变控制式三轴仪进行加筋砂土的不固结不排水三轴剪切试验,探究土工格栅网格尺寸、加筋层数及围压对砂土强度特性的影响。试验结果表明:未加筋时,砂土主要表现为中上部鼓胀破坏,随着加筋层数的增加,砂土的破坏形态依次转变为中部鼓胀破坏和剪切破坏;素砂和加筋砂土的偏应力-轴向应变曲线表现为应变软化型。不同网格尺寸的土工格栅对砂土的强度特性影响不同,土工格栅网格尺寸为 $ 3\ mm\times3\ mm $时,加筋效果类似硬化的“土工布”;1层土工格栅加筋时,随着土工格栅网格尺寸的减小,对砂土的强度影响不大;2、3层土工格栅加筋时,网格尺寸越小,加筋效果越好;加土工格栅可有效提高砂土的黏聚力,当土工格栅网格尺寸较小时,土工格栅还可提高砂土的内摩擦角。

关键词: 土工格栅加筋；网格尺寸；强度特性；破坏形态；三轴试验

Funding

国家自然科学基金资助项目（51774107）

合肥工业大学学报(自然科学版)

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