Processing math: 0%
ISSN 1000-3665 CN 11-2202/P
  • 中文核心期刊
  • GeoRef收录期刊
  • Scopus 收录期刊
  • 中国科技核心期刊
  • DOAJ 收录期刊
  • CSCD(核心库)来源期刊
  • 《WJCI 报告》收录期刊
欢迎扫码关注“i环境微平台”

基于均匀化理论与上限分析的膨胀土滑坡稳定性分析

杨晓华, 王东清, 袁帅, 张毅

杨晓华,王东清,袁帅,等. 基于均匀化理论与上限分析的膨胀土滑坡稳定性分析[J]. 水文地质工程地质,2024,51(2): 172-182. DOI: 10.16030/j.cnki.issn.1000-3665.202302050
引用本文: 杨晓华,王东清,袁帅,等. 基于均匀化理论与上限分析的膨胀土滑坡稳定性分析[J]. 水文地质工程地质,2024,51(2): 172-182. DOI: 10.16030/j.cnki.issn.1000-3665.202302050
YANG Xiaohua, WANG Dongqing, YUAN Shuai, et al. Stability analysis of expansive soil landslide based on homogenization theory and upper limit analysis[J]. Hydrogeology & Engineering Geology, 2024, 51(2): 172-182. DOI: 10.16030/j.cnki.issn.1000-3665.202302050
Citation: YANG Xiaohua, WANG Dongqing, YUAN Shuai, et al. Stability analysis of expansive soil landslide based on homogenization theory and upper limit analysis[J]. Hydrogeology & Engineering Geology, 2024, 51(2): 172-182. DOI: 10.16030/j.cnki.issn.1000-3665.202302050

基于均匀化理论与上限分析的膨胀土滑坡稳定性分析

基金项目: 国家自然科学基金项目(51908053)
详细信息
    作者简介:

    杨晓华(1961—),男,博士,教授,博士生导师,主要从事岩土与隧道工程研究。E-mail:xiaohuay@126.com

    通讯作者:

    王东清(1997—),男,博士研究生,主要从事岩土工程研究。E-mail:wangdqchd@qq.com

  • 中图分类号: P642.22

Stability analysis of expansive soil landslide based on homogenization theory and upper limit analysis

Funds: This research is supported by the National Natural Science Foundation of China(Grant No. 51908053)
  • 摘要:

    在膨胀土和滑坡共同作用下,隧道洞口段施工更容易引发地表开裂甚至滑坡等工程灾害,在隧道内采用微型桩群防治滑坡比抗滑桩具有优势。本文基于均匀化理论与上限分析对某高速公路隧道洞口段膨胀土滑坡的稳定性进行计算,并评价微型桩群和削方卸载不同组合方式的处置效果,计算时将微型桩群及桩周土通过均匀化理论等效为符合摩尔库仑强度准则的等效加固体来,以此提高计算效率,最后通过对现场削方+微型桩群加固处置后的滑坡变形监测来验证计算的合理性,得出如下结论:相较于土的强度参数,等效加固体内摩擦角保持不变,黏聚力从26 kPa提高到85.36 kPa。处置前后的滑坡稳定性评价结果表明,不做处理时,滑坡滑动面从滑坡上方岩土交界面延续到隧道洞口前;仅采用微型桩群加固时,滑坡安全系数在1.17左右,滑动面从岩土交界面延续到隧道洞口后;同时采用微型桩群加固和削方卸载时,滑坡安全系数提高到1.26~1.28,滑动面上缘由土石交界面前移。现场变形监测表明地表变形与深层土体变形均不超过3 mm,该措施能保障滑坡的稳定性,同时也验证了计算方法的合理性,可为同类工程提供参考。

    Abstract:

    Under the forces of expansive soil and landslides, the construction of the tunnel entrance is more likely to cause engineering disasters, such as surface cracking and landslides. The application of micro piles in the tunnel has advantages over anti slide piles. Based on the homogenization theory and upper limit analysis, this study calculates the stability of expansive soil landslide at the entrance of an expressway tunnel, and evaluates the treatment effect of different combinations of micro pile groups and cutting-unloading. In the calculation, to improve the calculation efficiency, the micro pile groups and soil around the piles are equivalent to the plus solid conforming to the Mohr-Coulomb strength criterion based on the homogenization theory. the results then are verified by monitoring the landslide deformation after the cutting and micro pile group reinforcement treatment in the field. This study indicates that compared with the strength parameters of soil, the internal friction angle of equivalent reinforcement remains constant, and the cohesion increases from 26 kPa to 85.36 kPa. The evaluated landslide stability before and after treatment show that the sliding surface of the landslide extends from the rock-soil interface above the landslide to the front of the tunnel portal without treatment; when only using micro pile group reinforcement, the landslide safety factor is about 1.17, and the sliding surface extends from the rock-soil interface to the tunnel portal; when only using both micro pile group reinforcement and cutting-unloading, the safety factor increases from 1.26 to 1.28, and the upper edge of the sliding surface moves forward from the rock-soil interface. The field deformation monitoring shows that the deformation of surface and deep soil are less than 3 mm, which can keep the landslide stable, and also verifies the effectiveness of the calculation method. This study provides beneficial information for similar projects.

  • 岩土工程稳定性计算常用的方法有极限平衡法、滑移线法、弹塑性增量有限元法和极限分析法[13]。基于经典塑性力学的极限分析方法是一种求解结构极限承载力的直接算法,能够得到临界荷载严格的上限及下限,可以通过上下限之间的差值直观判断结果的计算精度[46]。下限分析从构建静力许可应力场出发,计算出满足条件的最大外荷载;上限分析考虑塑性区和滑裂面上的运动许可速度场,从而得到极限荷载的上限。极限分析理论具有较为严密的理论基础,在计算滑坡稳定性时能够以较小的计算代价得到坡体的极限荷载和安全系数[78]

    微型桩具有施工简便、机械化程度高、工期短见效快等特点,作为一种轻型抗滑措施,也常用于散堆积型土石混合边坡或碎裂型岩质边坡[914]。采用数值极限分析的方法对大范围布设微型桩群的滑坡进行治理效果评价时,如果显式考虑所有微型桩,在单元离散过程中就会产生大量的小尺寸单元,极大增加计算量。为了在极限分析的迭代中简化计算,通过均匀化理论将微型桩和桩间土均匀化为等效加固体。对于桩土形成的复合材料,可以通过对桩和土破坏形式进行严格的力学推导得到一个新的本构模型,使得均匀化之后的材料破坏与桩土复合材料破坏形式接近[1516]。也有研究先从复合材料中取出具有代表性的单胞模型,将单胞模型均匀化之后再应用到宏观层面,从而得到均匀化之后复合材料的力学特性[1718]。此外,如果复合材料中的组成和结构具有周期性重复排列的特点即为周期性复合材料,在均匀化时可以将单胞模型缩小至周期重复出现的最小组成和结构,并为其施加周期性边界条件,通过给单胞体加载获得其应力应变特性,实现均匀化[19]。这些方法所确定的均匀化模型中参数较多且具有一定局限性,并不能直接用于桩群加固处置滑坡后的稳定性计算。因此需要探索一种可以用于强度折减极限分析的均匀化方法,降低迭代计算量。

    本文以某高速公路隧道洞口段膨胀土滑坡治理为工程依托,将梅花形布置的微型桩群和桩周土视为周期性材料,把单桩及桩周土视为单胞体,通过数值三轴试验的方法最终得到符合摩尔库仑强度准则的等效加固体强度参数,然后采用强度折减数值极限分析的方法,对采用微型桩群加固和削方卸载的组合措施治理前后的洞口段滑坡的稳定性进行评价。最后通过处置后滑坡的变形监测来反映边坡所处状态[2021],验证计算方法的合理性,为此类地区的工程建设提供参考。

    某高速公路隧道位于河南省西峡县西坪镇境内,洞口段70 m左右为弱膨胀坡积黏土滑坡。隧道平面和地质纵断面分别如图1图2所示,洞口滑坡段为土岩结合地层,其中隧道中部围岩为元古界强-中风化石英闪长岩,向洞口逐渐过渡为第四系洪积层和残坡积层含碎石黏土。通过室内膨胀特性试验表明含水率不同,土膨胀力差异巨大,当含水率为12%时,膨胀力在150 kPa左右,约为30%含水率的25倍。

    图  1  场地平面图
    Figure  1.  Topographic map of project site
    图  2  地质纵断面
    Figure  2.  Geological profile in the study area

    隧道施工期间正值雨季,滑坡体出现明显的地表裂缝与局部滑移,部分降雨渗入滑坡体,使滑动面土体抗剪强度降低,发生剪切蠕动变形,如图3所示。地质勘测结果表明,滑坡区域的黏土层含水率较大,土体强度较低,部分钻孔出现缩颈甚至塌孔现象,认为滑坡体为欠稳定状态,处于蠕动变形阶段。

    图  3  洞口段地表裂缝
    Figure  3.  Surface cracks in the tunnel portal section

    袁帅等[78]在上限分析中应用了一种当所有边都是直边便可保证其结果是严格的线性应变单元[22],单元内的速度场为:

    \dot{{\boldsymbol{U}}}=\left[\begin{array}{*{20}{c}}\dot{{\boldsymbol{u}}} & \dot{{\boldsymbol{v}}} & \dot{{\boldsymbol{w}}}\end{array}\right]^{\text{T}}={\boldsymbol{N}}_{\text{ε}}\dot{{\boldsymbol{d}}}_{\mathrm{e}} (1)

    式中:\dot {\boldsymbol{U}} ——单元内的速度场;

    \dot {\boldsymbol{u}} \dot{\boldsymbol{ v}}\dot {\boldsymbol{w}}——速度的3个分量;

    {\boldsymbol{N}}_{\text{ε}} ——包含应变型函数的系数矩阵;

    {{\dot {{\boldsymbol{d}}}}_{\mathrm{e}}}——单元速度矢量。

    四面体单元内部的应力矢量可表示为:

    \sigma (x) = \sum\limits_1^4 {{L_i}(x){\sigma _i}} = {{\boldsymbol{N}}_{\text{σ}} }{{\boldsymbol{\sigma}} _{\mathrm{e}}} (2)

    式中: {{\boldsymbol{N}}_{\text{σ}} } ——包含应力形函数的系数矩阵;

    {{\boldsymbol{\sigma}} _{\mathrm{e}}} ——单元应力矢量。

    于是可得:

    \begin{split} &\max \;\lambda \\ &{\mathrm{s.t}}. \quad {\boldsymbol{A}}{{\boldsymbol{\sigma}} _{\mathrm{g}}} = \lambda q + {q_0} \end{split} (3)
    f(\sigma_i)\leqslant0\quad(i=1,2,\cdots,4N_{\mathrm{e}})

    式中: \boldsymbol{\sigma}_{\mathrm{g}} ——整体应力矢量;

    q——整体荷载矢量;

    q0——整体给定力矢量;

    Ne——单元数量;

    A——受力平衡有关的系数矩阵。

    假设土体满足摩尔库仑强度准则,并采用半正定锥规划对摩尔库仑模型的非线性优化问题进行求解,设:

    {\boldsymbol{\gamma}} ={\mathrm{ mat}}(\sigma ) = \left[ {\begin{array}{*{20}{c}} {{\sigma _{11}}}&{{\sigma _{12}}}&{{\sigma _{13}}} \\ {{\sigma _{12}}}&{{\sigma _{22}}}&{{\sigma _{23}}} \\ {{\sigma _{13}}}&{{\sigma _{23}}}&{{\sigma _{33}}} \end{array}} \right] (4)

    γ > 0,则γ 为半正定对称矩阵。摩尔库仑强度准则的半正定锥表达形式为:

    \gamma + \beta {\boldsymbol{I}} \geqslant 0
    - \gamma + (k - \alpha \beta ){\boldsymbol{I}} \geqslant 0 (5)

    式中:I——单位矩阵;

    β——辅助变量;

    \alpha = \dfrac{{1 + \sin \varphi }}{{1 - \sin \varphi }}k = 2c\dfrac{{\cos \varphi }}{{1 - \sin \varphi }}

    结合式(6),得到该模型的数学规划问题:

    \begin{split} &\max \lambda \\ &{\mathrm{s.t}}.\quad A{\sigma ^g} = \lambda q + {q_0} \end{split}
    \sigma _i^ + = {\sigma _i} + {\beta _i}m
    \sigma _i^ - = - {\sigma _i} + \left( {{k_i} - {\alpha _i}{\beta _i}} \right)m
    \gamma _i^ + = {\mathrm{mat}}(\sigma _i^ + ) \geqslant 0
    {\boldsymbol{\gamma}} _i^ - = {\mathrm{mat}}(\sigma _i^ - ) \geqslant 0 (6)

    式中:i = 1, 2, ···, 4Ne

    m——单位辅助向量, \boldsymbol{m}=[1\; \; 1\; \; 1\; \; 0\; \; 0\; \; 0]^{\text{T}}

    上限分析强度折减在进行稳定性计算时,不断折减边坡的强度参数,直至算出来的极限重度等于土体实际的重度,此时强度参数的折减系数K1即为边坡的安全系数:

    1 = \frac{{\displaystyle\int {\dfrac{c}{{{K_1}}} + \sigma \dfrac{{\tan \varphi }}{{{K_1}}}{\text{d}}S} }}{{\displaystyle\int {\tau {\text{d}}S} }} = \frac{{\displaystyle\int {{c_1} + \sigma \tan {\varphi _1}{\text{d}}S} }}{{\displaystyle\int {\tau {\text{d}}S} }} (7)

    式中:dS——求解域面积增量;

    {c_1} = \dfrac{c}{{{K_1}}}

    \tan {\varphi _1} = \dfrac{{\tan \varphi }}{{{K_1}}}

    τ——潜在滑动面的实际剪应力。

    周期性复合材料中要求其结构和组成具有周期性排列的特点,并把周期性重复的最小结构称为单胞体。在微型桩群形成的桩土加固体中,桩的尺寸远小于桩群加固体的尺寸,加固体破坏前,整体性较好,桩土产生的差异变形较小,再加之微型桩在加固体中采用梅花形布置,排列符合周期性重复规律,因此可以将微型桩及桩间土视为一种周期性材料。取单桩及其周边土组成单胞体,在单胞体六个边界面上施加周期性边界条件,通过数值三轴压缩试验研究桩土单胞体的力学特性,最终获得等效加固体的宏观强度参数,如图4所示。

    图  4  周期性材料均匀化示意图
    Figure  4.  Schematic diagram of periodic material homogenization

    对于单胞体,其内部任一点的位移场{\mu _i}可表示为:

    \mu_i=\overline{\varepsilon}_{ij}x_j+\mu_i^*\ \ (i、j=1,\ 2,\ 3) (8)

    式中:{\mu _i}——某点的位移场;

    {\bar \varepsilon _{ij}}——单胞平均应变;

    {x_j}——单胞内任一点坐标;

    \mu _i^*——边界周期性位移修正量,是未知量。

    建模时,将模型建立为立方体,3对平行面上的结点对应重合,在沿Xkk=1,2,3)方向上,式(8)可表示为:

    \mu _i^{(k + )} = {\bar \varepsilon _{ij}}x_j^{(k + )} + \mu _i^* (9)
    \mu _i^{(k - )} = {\bar \varepsilon _{ij}}x_j^{(k - )} + \mu _i^* (10)

    式中:k+k——沿Xk正负方向平行的单胞体周期性边界。

    式(9)、式(10)相减可得周期性条件,即式(11):

    \mu _i^{(k + )} - \mu _i^{(k - )} = {\bar \varepsilon _{ij}}\left( {x_j^{(k + )} - x_j^{(k - )}} \right) = {\bar \varepsilon _{ij}}\Delta {x_j} (11)

    在ABAQUS中建立施加周期性边界条件的单胞体模型,为了模拟桩土相互作用在桩与土层之间加一层软弱的桩土夹层,单胞体模型和计算选取的材料参数分别如图5表1所示。数值三轴试验的围压设为100,200,300,400 kPa,加载至单胞体发生整体塑性破坏,四种工况的数值三轴试验计算结果塑性区云图如图6所示。将单胞体模型计算结果的单元节点应力导出,按式(12)计算出单胞体的体平均应力,确定体平均应力的3个应力不变量,然后得出单胞体平均主应力。

    图  5  单胞体模型数值三轴试验周期性边界条件与施加荷载
    Figure  5.  Periodic boundary conditions and applied loads in the numerical triaxial test of cell model
    表  1  单胞体模型材料参数表
    Table  1.  Material parameters of cell model
    名称重度/(kN·m−3黏聚力/kPa内摩擦角/(°)弹性模量/MPa屈服强度/MPa泊松比
    21 6002350.33
    膨胀土地基1826.0152800.34
    桩土夹层1820.81222400.34
    下载: 导出CSV 
    | 显示表格
    图  6  单胞体模型数值三轴试验结果
    Figure  6.  Results in the numerical triaxial test of cell model
    \overline{\sigma}= \frac{1}{V}\int\limits_\Omega {\sigma (x){\text{d}}V} (12)

    式中:\overline{\sigma}\dot{U}——单胞体的体平均应力;

    \sigma (x) ——单元节点应力矩阵;

    V——求解域体积;

    Ω——单元求解域。

    根据单胞体平均大小主应力绘出莫尔圆与强度包线,如图7所示,最终确定单胞体均匀化之后的摩尔库仑强度参数,黏聚力c为86.36 kPa,内摩擦角φ为15°。相较于桩周土体的强度参数(c=26 kPa,φ=15°),在采用微型桩群处置隧道基底时,微型桩群对土体的加固,相当于提高了土体的黏聚力。

    图  7  单胞体等效摩尔库仑强度曲线(单位:kPa)
    Figure  7.  Equivalent molar coulomb strength curve of single cell (unit:kPa)

    等效加固体的强度参数确定之后,在ABAQUS中建立三种工况的滑坡模型,包括滑坡未处理、仅有微型桩加固以及削坡和微型桩加固的工况,并对其进行单元离散,如图8所示。其中将微型桩群转化为等效加固体的形式计算,采用摩尔库仑模型,强度参数采用单胞体三轴压缩试验确定的cφ值,膨胀土的膨胀力综合考虑室内膨胀试验与现场实际情况设为100 kPa,其他参数根据地勘和工程设计确定,模型的材料参数如表2所示。计算时将模型的单元节点信息导入Matlab,采用mosek优化求解器计算,得到滑坡的安全系数,结合塑性耗散和速度场判断滑动面位置。

    图  8  滑坡计算模型
    Figure  8.  Landslide calculation model
    表  2  滑坡模型材料参数表
    Table  2.  Material parameters of landslide model
    名称 重度
    /(kN·m−3
    黏聚力
    /kPa
    内摩擦角
    /(°)
    抗压强度
    /MPa
    抗拉强度
    /MPa
    闪长石地层 20 60 20
    膨胀土地层 18 26 15
    隧道支护 25 26 1.6
    等效加固体 18 86.36 15
    下载: 导出CSV 
    | 显示表格

    处置前对滑坡的变形进行检测,测点与测斜孔如图9所示,在隧道施工的75 d内,滑坡体最大地表变形超过50 mm,且地表与深层土体变形仍呈现出继续发展的趋势。经勘测滑坡后缘处于桩号K10+030地表裂缝处,前缘在洞口附近,滑坡体最大厚度为25 m。

    图  9  测点与测斜孔布置图
    Figure  9.  Layout of measuring points and inclined holes

    图10图11分别为滑坡未处理工况的滑坡塑性耗散和速度场云图,由云图可知滑坡的滑动面后缘为土岩交界面,滑动面下缘略低于隧道基底,并延续到隧道洞口,这与地质勘测得出的滑动面结果较为一致。由图11的速度场可知,滑坡在膨胀力作用下,滑坡出现整体滑动破坏,隧道和滑坡呈现共同运动的趋势,即滑坡不采取处理措施时,在膨胀力的作用下,滑坡和隧道都处于不稳定状态。边坡不做处理时,计算得到的安全系数为0.953。

    图  10  未处理时的滑坡塑性耗散
    Figure  10.  Plastic dissipation of landslide without treatment
    图  11  未处理时的滑坡速度场
    Figure  11.  Velocity field of landslide when it is not treated

    K10+075 至 K10+145范围内隧道基底采用6 m的微型桩群加固后的塑性耗散和速度场如图12图13所示,滑坡体的破坏状态与未处理时相似,呈现出整体滑动破坏,但破坏范围较小。相比于未处理时,滑动面前缘向后移动,在隧道洞口附近。从滑坡整体速度场和隧道中线剖面的速度场来看,微型桩群加固后,隧道支护结构处于稳定状态,隧道上方的土体在膨胀力作用下发生局部滑动破坏,而隧道下方的土体并未发生破坏。说明隧道基底的微型桩群,不仅可以提高隧道支护结构的稳定性,对滑坡整体的抗滑稳定性也有一定的作用。通过计算,仅采用微型桩群加固时,滑坡的安全系数为1.17,滑坡处于相对稳定状态。

    图  12  采用微型桩群加固时的滑坡塑性耗散
    Figure  12.  Plastic dissipation of landslide strengthened by micro pile group
    图  13  采用微型桩群加固时的滑坡速度场
    Figure  13.  Velocity field of landslide reinforced by micro piles

    采用削方卸载和隧道基底处置后的塑性耗散和速度场如图14图15所示,滑坡整体滑动破坏的范围进一步缩小,这是由于削方减少了滑坡的荷载,再加上微型桩群的加固作用,使滑坡的稳定性得到增强。根据塑性耗散和速度场云图显示出的潜在滑动面可知,相比于仅做基底处置时,滑动面上缘从岩土交界面向前移动,滑动面前缘在隧道洞口附近,滑坡破坏范围进一步缩小。从隧道中线剖面的塑性耗散和速度场来看,隧道支护结构和它下方的土体处于稳定状态,隧道上方土体的滑动破坏范围也随着削方而变小。通过计算,采用削方卸载+微型桩群的措施处置后,滑坡的安全系数在1.26~1.28之间,满足规范对滑坡安全系数的要求,可以认为此措施可以保证滑坡体的稳定性。

    图  14  微型桩群加固与削方卸载工况的滑坡塑性耗散
    Figure  14.  Plastic dissipation of landslide under the condition of micro pile group reinforcement and cutting-unloading
    图  15  微型桩群加固与削方卸载工况的滑坡速度场
    Figure  15.  Velocity field of landslide under the condition of micro pile group reinforcement and earthwork cutting unloading

    对滑坡采用削方和隧道基地加固的处置措施,削方范围洞顶地面标高399 m至坡脚裂缝后方土体地面标高423 m处,以裂缝辐射区域为界,总面积约3400 m2,如图16所示,削方后采用水泥土填封地表裂缝并在削方坡脚换填混凝土;在隧道洞内桩号K10+075 至 K10+145段采用Φ108 mm×6 mm钢管微型桩注水泥浆加固,桩长6 m,纵向间距1 m,每排8至10根桩,采用梅花形布置,空隙填充率不小于80%,要求注浆后地基承载力不低于350 kPa。加固后对滑坡体地表及深层土体变形进行监测,测斜钻孔布置如图9所示。

    图  16  边坡处置示意图
    Figure  16.  Schematic diagram of landslide treatment

    滑坡处置后地表变形和选取的测点深层土体位移如图17图18所示。工后105 d内,各个测点的地表变形基本稳定在3 mm以内,其中滑坡上部的3个测点地表变形除K10+030处达到2.69 mm外,另外两个测点变形不超过2.5 mm;滑坡中下部的K10+090和K10+150处的地表变形在1 mm左右。深层土体位移均不超过3 mm,其中位于滑坡上部K10+030和K10+070测点位移整体呈现出随深度减少的趋势,峰值变形出现在2~4 m范围内,最大变形不超过2.7 mm;位于滑坡下部的两个测点其中K10+120的变形稳定,最大变形出现在6~10 m范围内且不超过1 mm,K10+150测点在深度4~12 m范围内变形较大,变形达到2.2 mm左右。结合地表变形和深层土体位移可知,对滑坡进行削坡和隧道基底处理之后,工后105 d各个测点的最大变形不超过3 mm,可以认为滑坡处于稳定状态,同时表明采用“削坡卸载 + 洞内基底加固”的措施能保障滑坡的稳定性,与数值计算结果吻合,也验证了计算方法的合理性。

    图  17  滑坡处置后测点的地表变形
    Figure  17.  Surface deformation of landslide after treatment
    图  18  滑坡处置后滑坡体深层土体位移
    Figure  18.  Displacement of deep soil after landslide treatment

    (1)将微型桩群与桩周土视作周期性材料,通过桩土单胞体数值三轴试验得到其宏观强度参数,最终得到的内摩擦角和土体保持一致,黏聚力从26 kPa提高到86.36 kPa,该方法将复杂的桩土加固体转化为参数较少的等效加固体在应用于边坡稳定性分析可以减小迭代时的计算量。

    (2)滑坡不做处理时,安全系数在1.06左右,滑动面从滑坡上方岩土交界面延续到隧道洞口前。滑坡仅做微型桩群处理时,滑坡和隧道支护结构的稳定性得到一定程度的增强,滑坡安全系数提升到1.17左右,潜在滑动面从岩土交界面延续到隧道洞口后附近。

    (3)当滑坡采取基底处置和削方卸载时,滑坡安全系数提高到1.26~1.28之间,潜在滑动面上缘由土石交界面前移并延续到隧道洞口后。根据数值计算结果,削方卸载和基底处置的措施可以保障滑坡的安全。

    (4)采用削方和基底加固处置后滑坡体变形得到控制,地表变形测点在工后105 d内变形不超过3 mm,深层土体变形最值普遍在2.0~2.7 mm之间,表明该措施能保障滑坡的稳定性。

  • 图  1   场地平面图

    Figure  1.   Topographic map of project site

    图  2   地质纵断面

    Figure  2.   Geological profile in the study area

    图  3   洞口段地表裂缝

    Figure  3.   Surface cracks in the tunnel portal section

    图  4   周期性材料均匀化示意图

    Figure  4.   Schematic diagram of periodic material homogenization

    图  5   单胞体模型数值三轴试验周期性边界条件与施加荷载

    Figure  5.   Periodic boundary conditions and applied loads in the numerical triaxial test of cell model

    图  6   单胞体模型数值三轴试验结果

    Figure  6.   Results in the numerical triaxial test of cell model

    图  7   单胞体等效摩尔库仑强度曲线(单位:kPa)

    Figure  7.   Equivalent molar coulomb strength curve of single cell (unit:kPa)

    图  8   滑坡计算模型

    Figure  8.   Landslide calculation model

    图  9   测点与测斜孔布置图

    Figure  9.   Layout of measuring points and inclined holes

    图  10   未处理时的滑坡塑性耗散

    Figure  10.   Plastic dissipation of landslide without treatment

    图  11   未处理时的滑坡速度场

    Figure  11.   Velocity field of landslide when it is not treated

    图  12   采用微型桩群加固时的滑坡塑性耗散

    Figure  12.   Plastic dissipation of landslide strengthened by micro pile group

    图  13   采用微型桩群加固时的滑坡速度场

    Figure  13.   Velocity field of landslide reinforced by micro piles

    图  14   微型桩群加固与削方卸载工况的滑坡塑性耗散

    Figure  14.   Plastic dissipation of landslide under the condition of micro pile group reinforcement and cutting-unloading

    图  15   微型桩群加固与削方卸载工况的滑坡速度场

    Figure  15.   Velocity field of landslide under the condition of micro pile group reinforcement and earthwork cutting unloading

    图  16   边坡处置示意图

    Figure  16.   Schematic diagram of landslide treatment

    图  17   滑坡处置后测点的地表变形

    Figure  17.   Surface deformation of landslide after treatment

    图  18   滑坡处置后滑坡体深层土体位移

    Figure  18.   Displacement of deep soil after landslide treatment

    表  1   单胞体模型材料参数表

    Table  1   Material parameters of cell model

    名称重度/(kN·m−3黏聚力/kPa内摩擦角/(°)弹性模量/MPa屈服强度/MPa泊松比
    21 6002350.33
    膨胀土地基1826.0152800.34
    桩土夹层1820.81222400.34
    下载: 导出CSV

    表  2   滑坡模型材料参数表

    Table  2   Material parameters of landslide model

    名称 重度
    /(kN·m−3
    黏聚力
    /kPa
    内摩擦角
    /(°)
    抗压强度
    /MPa
    抗拉强度
    /MPa
    闪长石地层 20 60 20
    膨胀土地层 18 26 15
    隧道支护 25 26 1.6
    等效加固体 18 86.36 15
    下载: 导出CSV
  • [1] 李宁,刘冠麟,许建聪,等. 降雨条件下边坡有限元强度折减法计算平台开发及其应用[J]. 水文地质工程地质,2018,45(3):63 − 70. [LI Ning,LIU Guanlin,XU Jiancong,et al. Development of shear strength reduction method for slope stability analysis under rainfall conditions and its application[J]. Hydrogeology & Engineering Geology,2018,45(3):63 − 70. (in Chinese with English abstract)]

    LI Ning, LIU Guanlin, XU Jiancong, et al. Development of shear strength reduction method for slope stability analysis under rainfall conditions and its application[J]. Hydrogeology & Engineering Geology, 2018, 453): 6370. (in Chinese with English abstract)

    [2] 王平,朱赛楠,张枝华,等. 三峡库区大型斜倾顺层滑坡失稳机理分析——以石柱县龙井滑坡为例[J]. 中国地质灾害与防治学报,2021,32(4):24 − 32. [WANG Ping,ZHU Sainan,ZHANG Zhihua,et al. Instability mechanism of massive oblique bedding rock landslide in the Three-Gorges Reservoir:a case study of the Longjing landslide in Shizhu County of Chongqing City[J]. The Chinese Journal of Geological Hazard and Control,2021,32(4):24 − 32. (in Chinese with English abstract)]

    WANG Ping, ZHU Sainan, ZHANG Zhihua, et al. Instability mechanism of massive oblique bedding rock landslide in the Three-Gorges Reservoir: a case study of the Longjing landslide in Shizhu County of Chongqing City[J]. The Chinese Journal of Geological Hazard and Control, 2021, 324): 2432. (in Chinese with English abstract)

    [3] 陈新泽,唐辉明,杨有成,等. 基于FLAC3D强度折减法滑坡三维稳定性研究——以三峡库区白果树古滑坡群为例[J]. 水文地质工程地质,2008,35(2):24 − 29. [CHEN Xinze,TANG Huiming,YANG Youcheng,et al. 3D analysis of landslide stability based on strength reduction FLAC3D:Taking Baiguoshu paleo-landslide group in the Three Gorges Reservoir area as example[J]. Hydrogeology & Engineering Geology,2008,35(2):24 − 29. (in Chinese with English abstract)] DOI: 10.3969/j.issn.1000-3665.2008.02.005

    CHEN Xinze, TANG Huiming, YANG Youcheng, et al. 3D analysis of landslide stability based on strength reduction FLAC3D: Taking Baiguoshu paleo-landslide group in the Three Gorges Reservoir area as example[J]. Hydrogeology & Engineering Geology, 2008, 352): 2429. (in Chinese with English abstract) DOI: 10.3969/j.issn.1000-3665.2008.02.005

    [4] 王根龙,伍法权,李巨文. 折线型滑面边坡稳定系数计算的极限分析上限解[J]. 水文地质工程地质,2007,34(1):62 − 65. [WANG Genlong,WU Faquan,LI Juwen. Upper-bound solution of safety factor for slope with broken-line slip surface based on plasticity limit analysis[J]. Hydrogeology & Engineering Geology,2007,34(1):62 − 65. (in Chinese with English abstract)] DOI: 10.3969/j.issn.1000-3665.2007.01.013

    WANG Genlong, WU Faquan, LI Juwen. Upper-bound solution of safety factor for slope with broken-line slip surface based on plasticity limit analysis[J]. Hydrogeology & Engineering Geology, 2007, 341): 6265. (in Chinese with English abstract) DOI: 10.3969/j.issn.1000-3665.2007.01.013

    [5]

    LOW B K. Practical probabilistic slope stability analysis[J]. Soil and Rock America,2003,2:2777 − 2784.

    [6] 李春光,朱宇飞,刘丰,等. 基于下限原理有限元的强度折减法[J]. 岩土力学,2012,33(6):1816 − 1821. [LI Chunguang,ZHU Yufei,LIU Feng,et al. Evaluation of strength reduction factor by lower bound limit analysis using finite element method[J]. Rock and Soil Mechanics,2012,33(6):1816 − 1821. (in Chinese with English abstract)] DOI: 10.3969/j.issn.1000-7598.2012.06.033

    LI Chunguang, ZHU Yufei, LIU Feng, et al. Evaluation of strength reduction factor by lower bound limit analysis using finite element method[J]. Rock and Soil Mechanics, 2012, 336): 18161821. (in Chinese with English abstract) DOI: 10.3969/j.issn.1000-7598.2012.06.033

    [7] 袁帅,冯德旺,张森豪,等. 考虑水力参数空间变异性的盾构隧道开挖面稳定性分析[J]. 岩土力学,2022,43(11):3153 − 3162. [YUAN Shuai,FENG Dewang,ZHANG Senhao,et al. Stability analysis of shield tunnel excavation face considering spatial variability of hydraulic parameters[J]. Rock and Soil Mechanics,2022,43(11):3153 − 3162. (in Chinese with English abstract)]

    YUAN Shuai, FENG Dewang, ZHANG Senhao, et al. Stability analysis of shield tunnel excavation face considering spatial variability of hydraulic parameters[J]. Rock and Soil Mechanics, 2022, 4311): 31533162. (in Chinese with English abstract)

    [8] 袁帅,冯德旺. 考虑渗透系数各向异性的盾构隧道开挖面稳定性数值极限分析[J]. 同济大学学报(自然科学版),2020,48(12):1717 − 1725. [YUAN Shuai,FENG Dewang. Computational limit analysis of shield tunnel face with a consideration of permeability anisotropy[J]. Journal of Tongji University (Natural Science),2020,48(12):1717 − 1725. (in Chinese with English abstract)]

    YUAN Shuai, FENG Dewang. Computational limit analysis of shield tunnel face with a consideration of permeability anisotropy[J]. Journal of Tongji University (Natural Science), 2020, 4812): 17171725. (in Chinese with English abstract)

    [9] 张智超,陈育民. 微型桩-加筋土挡墙的模型试验和数值模拟分析[J]. 岩石力学与工程学报,2017,36(4):987 − 996. [ZHANG Zhichao,CHEN Yumin. Model test and numerical analysis of micropile-MSE wall[J]. Chinese Journal of Rock Mechanics and Engineering,2017,36(4):987 − 996. (in Chinese with English abstract)]

    ZHANG Zhichao, CHEN Yumin. Model test and numerical analysis of micropile-MSE wall[J]. Chinese Journal of Rock Mechanics and Engineering, 2017, 364): 987996. (in Chinese with English abstract)

    [10] 王祥. 微型桩在高速铁路滑坡治理中的设计和应用[J]. 铁道工程学报,2021,38(2):19 − 22. [WANG Xiang. Design and application of micropiles on treatment for landslide of high-speed railway[J]. Journal of Railway Engineering Society,2021,38(2):19 − 22. (in Chinese with English abstract)] DOI: 10.3969/j.issn.1006-2106.2021.02.004

    WANG Xiang. Design and application of micropiles on treatment for landslide of high-speed railway[J]. Journal of Railway Engineering Society, 2021, 382): 1922. (in Chinese with English abstract) DOI: 10.3969/j.issn.1006-2106.2021.02.004

    [11] 高建章,方迎潮,王学军,等. 山区天然气管道—滑坡体系下花管微型桩与螺纹微型桩支护性能对比试验[J]. 中国地质灾害与防治学报,2023,34(2):120 − 131. [GAO Jianzhang,FANG Yingchao,WANG Xuejun,et al. Physical model tests on supporting performance of micro-pile and micro-pile with thread in natural gas pipe-landslide system in mountainous area[J]. The Chinese Journal of Geological Hazard and Control,2023,34(2):120 − 131. (in Chinese with English abstract)]

    GAO Jianzhang, FANG Yingchao, WANG Xuejun, et al. Physical model tests on supporting performance of micro-pile and micro-pile with thread in natural gas pipe-landslide system in mountainous area[J]. The Chinese Journal of Geological Hazard and Control, 2023, 342): 120131. (in Chinese with English abstract)

    [12] 李乾坤,石胜伟,韩新强,等. 某滑坡治理工程微型组合抗滑桩应用效果分析[J]. 中国地质灾害与防治学报,2013,24(3):62 − 67. [LI Qiankun,SHI Shengwei,HAN Xinqiang,et al. Effects of the micro-piles to stabilize a slope[J]. The Chinese Journal of Geological Hazard and Control,2013,24(3):62 − 67. (in Chinese with English abstract)]

    LI Qiankun, SHI Shengwei, HAN Xinqiang, et al. Effects of the micro-piles to stabilize a slope[J]. The Chinese Journal of Geological Hazard and Control, 2013, 243): 6267. (in Chinese with English abstract)

    [13] 王树丰,张遵遵,赵欣. 桩心配筋微型桩抗滑特性试验研究[J]. 水文地质工程地质,2012,39(3):49 − 53. [WANG Shufeng,ZHANG Zunzun,ZHAO Xin. Model experimental research on anti-sliding characteristics of micropiles with center reinforcement arrangement[J]. Hydrogeology & Engineering Geology,2012,39(3):49 − 53. (in Chinese with English abstract)]

    WANG Shufeng, ZHANG Zunzun, ZHAO Xin. Model experimental research on anti-sliding characteristics of micropiles with center reinforcement arrangement[J]. Hydrogeology & Engineering Geology, 2012, 393): 4953. (in Chinese with English abstract)

    [14] 胡时友,蔡强,李超杰. 三排微型桩加固碎石土滑坡物理模型试验研究[J]. 水文地质工程地质,2018,45(3):56 − 62. [HU Shiyou,CAI Qiang,LI Chaojie. A study of the physical model test of debris landslide reinforcement with three row micro-piles[J]. Hydrogeology & Engineering Geology,2018,45(3):56 − 62. (in Chinese with English abstract)]

    HU Shiyou, CAI Qiang, LI Chaojie. A study of the physical model test of debris landslide reinforcement with three row micro-piles[J]. Hydrogeology & Engineering Geology, 2018, 453): 5662. (in Chinese with English abstract)

    [15]

    HASSEN G,GUEGUIN M,DE BUHAN P. A homogenization approach for assessing the yield strength properties of stone column reinforced soils[J]. European Journal of Mechanics - A/Solids,2013,37:266 − 280. DOI: 10.1016/j.euromechsol.2012.07.003

    [16]

    GUEGUIN M,HASSEN G,DE BUHAN P. Stability analysis of homogenized stone column reinforced foundations using a numerical yield design approach[J]. Computers and Geotechnics,2015,64:10 − 19. DOI: 10.1016/j.compgeo.2014.11.001

    [17]

    JELLALI B,BOUASSIDA M,DE BUHAN P. A homogenization method for estimating the bearing capacity of soils reinforced by columns[J]. International Journal for Numerical and Analytical Methods in Geomechanics,2005,29(10):989 − 1004. DOI: 10.1002/nag.441

    [18]

    MENG Qingxiang,WANG Huanling,XU Weiya,et al. A numerical homogenization study of the elastic property of a soil-rock mixture using random mesostructure generation[J]. Computers and Geotechnics,2018,98:48 − 57. DOI: 10.1016/j.compgeo.2018.01.015

    [19]

    WU Chengqing,HAO Hong. Derivation of 3D masonry properties using numerical homogenization technique[J]. International Journal for Numerical Methods in Engineering,2006,66(11):1717 − 1737. DOI: 10.1002/nme.1537

    [20] 李刚,王刚,高幼龙,等. 固定式钻孔倾斜仪在滑坡示范监测中的应用[J]. 水文地质工程地质,2009,36(4):135 − 138. [LI Gang,WANG Gang,GAO Youlong,et al. Application of EL in-place inclinmoter to landslide monitoring[J]. Hydrogeology & Engineering Geology,2009,36(4):135 − 138. (in Chinese with English abstract)] DOI: 10.3969/j.issn.1000-3665.2009.04.030

    LI Gang, WANG Gang, GAO Youlong, et al. Application of EL in-place inclinmoter to landslide monitoring[J]. Hydrogeology & Engineering Geology, 2009, 364): 135138. (in Chinese with English abstract) DOI: 10.3969/j.issn.1000-3665.2009.04.030

    [21] 陈云生,刘光彬,张一铭,等. 阳鹿高速公路K52新滑坡变形特征与成因机理分析[J]. 中国地质灾害与防治学报,2022,33(1):83 − 91. [CHEN Yunsheng,LIU Guangbin,ZHANG Yiming,et al. Deformation characteristics and genetic mechanism of a new landslide at K52 of Luyang freeway[J]. The Chinese Journal of Geological Hazard and Control,2022,33(1):83 − 91. (in Chinese with English abstract)]

    CHEN Yunsheng, LIU Guangbin, ZHANG Yiming, et al. Deformation characteristics and genetic mechanism of a new landslide at K52 of Luyang freeway[J]. The Chinese Journal of Geological Hazard and Control, 2022, 331): 8391. (in Chinese with English abstract)

    [22]

    MAKRODIMOPOULOS A,MARTIN C M. Upper bound limit analysis using simplex strain elements and second-order cone programming[J]. International Journal for Numerical and Analytical Methods in Geomechanics,2007,31(6):835 − 865. DOI: 10.1002/nag.567

  • 期刊类型引用(2)

    1. 李朝辉,张柯宏. 藏东南某滑坡成因分析及稳定性评价. 铁道勘察. 2025(01): 13-19 . 百度学术
    2. 程鹏军,张光荣. 洞口膨胀土滑坡桩基+横梁复合抗滑技术研究. 山西建筑. 2024(16): 65-69 . 百度学术

    其他类型引用(0)

图(18)  /  表(2)
计量
  • 文章访问数:  109
  • HTML全文浏览量:  8
  • PDF下载量:  31
  • 被引次数: 2
出版历程
  • 收稿日期:  2023-02-20
  • 修回日期:  2023-09-06
  • 录用日期:  2023-09-24
  • 网络出版日期:  2024-01-28
  • 刊出日期:  2024-03-14

目录

/

返回文章
返回