土工基础

土工基础 ›› 2019, Vol. 33 ›› Issue (6): 693-696.

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庄浪压实黄土的无侧限抗压强度及破坏特征

平凉-绵阳高速公路庄浪县段内广泛覆盖着II~IV级湿陷性黄土，为了更合理地选用高速公路筑路参数，有必要了解压实湿限性黄土的物理力学及破坏等基本特征。测试了庄浪压实湿陷性黄土的物理性质、矿物成分、击实特性，然后进行了无侧限抗压强度试验，获得了不同压实度和不同初始含水率条件下的压实湿陷性黄土的无侧限抗压强度和破坏模式，得出如下结论：(1)无侧限抗压强度随着压实度的增加显著增强，保持水分的能力也有所增强。(2)在初始含水率稍大于最优含水率的情况下，所获得的无侧限抗压强度最大，再提高初始含水率则会导致无侧限抗压强度的急剧降低。在工程实践中进行路基施工时，对于湿陷性黄土应尽量在稍湿的情况下进行压实为宜，但含水率不应超过最优含水率+3%；(3)随着压实度的增加，土体剪切破坏的特征愈发明显，压实度较高时，土体剪坏之后呈现出锥形的破坏模式。随着初始含水率的增加，土体破坏时的脆性破坏特征减弱，较高含水率时，土体破坏时呈现“侧胀”破坏特征。   

  1. （1.湖北省路桥集团有限公司，武汉 430056；2.中国科学院武汉岩土力学研究所，武汉 430071）
  • 收稿日期:2019-03-14 修回日期:2019-04-01 出版日期:2019-12-28 发布日期:2019-12-28
  • 作者简介:陆召松（1978-），男，工程师，研究方向为工程技术及管理。

The Unconfined Compressive Atrength and Failure Characteristics of Zhuanglang Compacted Collapsible Loess Soils

The collapsible loess of Level II~IV soils is widely distributed along the PingliangMianyan highway alignment. It is necessary to study the strength and failure characteristics for selecting better design parameters for the highway construction. In this paper, physical properties, mineral composition and compact characteristics of collapsible loess were extensively tested. Based on the unconfined compressive strength and failure characteristics tested under different degree of compactions and initial water contents, the conclusions could be made as follows: (1) The unconfined compressive strength and capacity of holding moisture are enhanced with increasing the degree of compaction; (2) The unconfined compressive strength achieved maximum value when the water contents were much higher than the optimum moisture content, however, the water content should not exceed 3% of the optimum moisture content; (3) The shear failure of soil samples was more and more obvious with the increasing degree of compactions, and conical failure mode was observed when the degree of compaction reached 100%. Brittle failure characteristics was less and less obvious with the increasing initial water contents, and lateral dilation behavior was presented when the water content reached 19%.   

  1. (1.Hubei Road and Bridge Co., Ltd., Wuhan 430056;
    2.Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071)
  • Received:2019-03-14 Revised:2019-04-01 Online:2019-12-28 Published:2019-12-28

摘要： 平凉-绵阳高速公路庄浪县段内广泛覆盖着II~IV级湿陷性黄土，为了更合理地选用高速公路筑路参数，有必要了解压实湿限性黄土的物理力学及破坏等基本特征。测试了庄浪压实湿陷性黄土的物理性质、矿物成分、击实特性，然后进行了无侧限抗压强度试验，获得了不同压实度和不同初始含水率条件下的压实湿陷性黄土的无侧限抗压强度和破坏模式，得出如下结论：(1)无侧限抗压强度随着压实度的增加显著增强，保持水分的能力也有所增强。(2)在初始含水率稍大于最优含水率的情况下，所获得的无侧限抗压强度最大，再提高初始含水率则会导致无侧限抗压强度的急剧降低。在工程实践中进行路基施工时，对于湿陷性黄土应尽量在稍湿的情况下进行压实为宜，但含水率不应超过最优含水率+3%；(3)随着压实度的增加，土体剪切破坏的特征愈发明显，压实度较高时，土体剪坏之后呈现出锥形的破坏模式。随着初始含水率的增加，土体破坏时的脆性破坏特征减弱，较高含水率时，土体破坏时呈现“侧胀”破坏特征。

关键词: 压实土, 湿陷性黄土, 无侧限抗压强度, 破坏特征

Abstract: The collapsible loess of Level II~IV soils is widely distributed along the PingliangMianyan highway alignment. It is necessary to study the strength and failure characteristics for selecting better design parameters for the highway construction. In this paper, physical properties, mineral composition and compact characteristics of collapsible loess were extensively tested. Based on the unconfined compressive strength and failure characteristics tested under different degree of compactions and initial water contents, the conclusions could be made as follows: (1) The unconfined compressive strength and capacity of holding moisture are enhanced with increasing the degree of compaction; (2) The unconfined compressive strength achieved maximum value when the water contents were much higher than the optimum moisture content, however, the water content should not exceed 3% of the optimum moisture content; (3) The shear failure of soil samples was more and more obvious with the increasing degree of compactions, and conical failure mode was observed when the degree of compaction reached 100%. Brittle failure characteristics was less and less obvious with the increasing initial water contents, and lateral dilation behavior was presented when the water content reached 19%.

Key words: Compacted Soil, Collapsible Loess, Unconfined Compressive Strength, Failure Characteristics

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