Soils and Foundations最新文献_第7页

Centrifuge model tests on liquefaction-induced settlement of river embankments reinforced by floating-type cement treatment method 浮式水泥加固河堤液化沉降离心模型试验

IF 3.3 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

Soils and Foundations

Pub Date : 2025-06-12 DOI: 10.1016/j.sandf.2025.101633

Masahide Otsubo , Yuta Miura, Kazuya Ueda, Shunsuke Tanimoto, Masanori Ishihara, Tetsuya Sasaki

Loose sandy soil layers are prone to liquefaction under strong earthquakes, causing damage to civil engineering structures inside or upon the liquefied ground. According to the present Japanese design guideline on liquefaction countermeasures for river levees, the entire depth of the liquefiable subsoil below river embankments should be improved. However, this approach is not economical against deep liquefiable subsoil. To rationalize the design approach, this contribution investigated the performance of a floating-type cement treatment method, in which only the shallower part of the liquefiable subsoil is reinforced. A series of centrifuge shaking table model tests was conducted under a 50

g

environment. The depth of improvement (cement treatment) was varied systematically, and the effect of the sloping ground was examined. The experimental results revealed that the settlements of river embankments can be reduced linearly by increasing the depth of improvement. Moreover, the acceleration of embankments can be reduced drastically by the vibration-isolation effect between the cement-treated soil and the liquefiable soil. These effects contribute to the safe retention of the embankment shape even when the liquefied sloping ground causes lateral flows. Towards practical implementation, discussions on the effect of permeability on cement-treated soil were expanded. Furthermore, the stress acting on cement-treated soil during shaking was measured using an acrylic block to explain the occurrence of cracks in the soil.

松散的沙质土层在强震作用下容易发生液化，对液化地面内部或上面的土木工程结构造成破坏。根据日本现行的河堤液化对策设计指南，应提高河堤以下可液化底土的整体深度。然而，对于深层可液化地基，这种方法并不经济。为了使设计方法合理化，本文研究了浮式水泥处理方法的性能，该方法仅对可液化地基的较浅部分进行加固。在50g环境下进行了一系列离心振动台模型试验。系统地改变了改善（水泥处理）的深度，并对倾斜地面的效果进行了检验。试验结果表明，增加堤防加固深度可以线性降低堤防沉降。此外，水泥处理土与液化土之间的隔振效应可以显著降低路堤的加速度。这些影响有助于即使在液化的倾斜地面引起横向流动时也能安全保持路堤形状。面向实际应用，扩展了对水泥土渗透性影响的讨论。此外，使用丙烯酸块测量了震动过程中作用在水泥处理土壤上的应力，以解释土壤中裂缝的发生。

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引用次数: 0

Rheological properties of deep-sea shallow sediments in the Western Pacific mining area 西太平洋矿区深海浅层沉积物的流变特性

IF 3.3 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

Soils and Foundations

Pub Date : 2025-06-01 DOI: 10.1016/j.sandf.2025.101632

Hao Liu , Zongxiang Xiu , Lejun Liu , Jie Dong , Qiuhong Xie , Mu Huang , Chenwei Luo , Yifeng Zeng , Xingsen Guo

Studying the rheological properties of deep-sea shallow sediments can provide basic mechanical characteristics for designing deep-sea mining vehicles driving on the soft seabed, providing anchoring stability of semi-submersible mining platforms, and assessing submarine landslide hazards. Shallow sediment column samples from the Western Pacific mining area were obtained, and their rheological properties were studied. A series of rheological tests was conducted under different conditions using an RST rheometer. In addition, conventional physical property, mineral composition, and microstructure analyses were conducted. The results showed that shallow sediments have a high liquid limit and plasticity, with flocculent and honeycomb-like flaky structures as the main microstructure types. The rheological properties exhibited typical non-Newtonian fluid characteristics with yield stress and shear-thinning phenomena during the shearing process. In contrast to previous studies on deep-sea soft soil sediments, a remarkable long-range shear-softening stage, called the thixotropic fluid stage, was discovered in the overall rheological curve. A four-stage model is proposed for the transition mechanism of deep-sea shallow sediments from the solid to liquid–solid, solid–liquid transition, thixotropic fluid, and stable fluid stages. The mechanism of the newly added thixotropic fluid stage was quantitatively analyzed using a modified Cross rheological model, and this stage was inferred from the perspective of mineralogy and microstructure. The results of this study can be useful for improving the operational safety and work efficiency of submarine operation equipment for deep-sea mining in the Western Pacific Ocean.

研究深海浅层沉积物的流变特性，可以为设计在软海底行驶的深海采矿车、提供半潜式采矿平台的锚固稳定性以及评估海底滑坡灾害提供基本的力学特性。获取了西太平洋矿区浅层沉积物柱样，对其流变特性进行了研究。利用RST流变仪在不同条件下进行了一系列流变试验。此外，还进行了常规物性、矿物组成和微观结构分析。结果表明：浅层沉积物具有较高的液限和塑性，以絮状和蜂窝状片状结构为主要微观结构类型；剪切过程中出现屈服应力和剪切变薄现象，流变特性表现出典型的非牛顿流体特性。与以往对深海软土沉积物的研究相比，在整体流变曲线中发现了一个显著的长时间剪切软化阶段，即触变流体阶段。提出了深海浅层沉积物从固体到液-固、固-液过渡、触变流体和稳定流体四个阶段的过渡机理模型。采用改进的Cross流变模型定量分析了新增触变流体阶段的机理，并从矿物学和微观结构的角度对该阶段进行了推断。研究结果可为提高西太平洋深海采矿潜艇作业设备的作业安全性和工作效率提供参考。

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引用次数: 0

Drilling parameters as predictors of the measured full scale performance of CFA piles by using statistical analysis of CPT profiles: a case study 利用CPT剖面的统计分析将钻孔参数作为CFA桩全尺寸性能的预测指标：一个案例研究

IF 3.3 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

Soils and Foundations

Pub Date : 2025-05-30 DOI: 10.1016/j.sandf.2025.101631

Gianpiero Russo , Ilaria Esposito , Massimo Ramondini , Alessia Vecchietti , Giacomo Russo

The Continuous Flight Auger (CFA) piles, also known as Auger Cast In Place piles (ACIP), have a widespread use in the world market of replacement concrete piles. The installation of such piles is generally made by equipment which records several significant installation parameters, as the torque M_t and the axial force N, applied during the auger advancing step. In the auger retrieval stage other parameters that can influence the load-settlement performance of the pile are monitored. The paper presents a case study dealing with the CFA piles adopted as a foundation for a water treatment basin. In the paper first the equations governing the kinematical analysis of the augering and concreting stages of the pile construction are introduced. After the description of the test site with the subsoil conditions and the presentation of a typical sets of parameters recorded during pile installation the results of two pile loading tests to failure are reported. A new approach for determining the depth of the soil layers boundaries, based on the statistical analysis of CPT profiles with depth, is proposed and successfully applied confirming the qualitative geological analysis of the site. A further statistical analysis is carried out to find a robust correlation between the q_c of the CPT and the torque M_t needed to screw in depth the auger for pile construction. Finally, virtual CPT profiles generated from the torque M_t recorded during the tested piles installation are used for piles bearing capacity calculations which are compared with the results of pile loading tests. The successful comparison reported in the paper is a first step to validate the proposal to use parameters recorded during augering to calculate and/or to confirm design values of the bearing capacity.

连续螺旋钻（CFA）桩，又称螺旋钻钻孔灌注桩（ACIP），在世界混凝土置换桩市场上有着广泛的应用。这种桩的安装通常由记录几个重要安装参数的设备进行，如扭矩Mt和轴向力N，在螺旋钻推进步骤中施加。在螺旋钻回收阶段，对影响桩荷载沉降性能的其他参数进行监测。本文以某水处理池地基采用CFA桩为例进行了分析。本文首先介绍了管桩施工旋钻阶段和砼阶段的运动学分析方程。在描述了试验场地的地基条件和桩安装过程中记录的一组典型参数之后，报告了两次桩荷载试验的破坏结果。基于CPT剖面随深度的统计分析，提出了一种确定土层边界深度的新方法，并成功应用于现场的定性地质分析。进行了进一步的统计分析，发现CPT的qc与螺旋钻入桩深所需的扭矩Mt之间存在强大的相关性。最后，利用试验桩安装过程中记录的扭矩Mt生成的虚拟CPT曲线进行桩承载力计算，并与桩载试验结果进行比较。本文报道的成功对比是验证利用螺旋钻过程中记录的参数来计算和/或确定承载力设计值的建议的第一步。

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引用次数: 0

Effect of pumice content on the undrained cyclic behaviour of pumiceous soil 浮石含量对浮石土不排水循环特性的影响

IF 3.3 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

Soils and Foundations

Pub Date : 2025-05-27 DOI: 10.1016/j.sandf.2025.101629

Emma Gardiner, Mark Stringer, Misko Cubrinovski, Sean Rees, Chris McGann

Pumice soil grains are characterized by their vesicular nature, which leads to lightweight, crushable grains with an extremely rough and angular surface texture. These characteristics give pumiceous soils particular engineering properties that are distinct from more commonly encountered hard-grained materials, making them problematic for engineers interested in assessing the risk and potential consequences of liquefaction. Natural pumice-rich soils are found with varying amounts of pumice; however, it remains unclear how the quantity of pumice present in a soil mixture alters the behaviour. This paper investigates the effect of pumice content on cyclic resistance using blends of a hard-grained sand and a pumice sand through a series of triaxial tests. Overall, the cyclic resistance was found to reduce with increasing pumice content. Furthermore, the cyclic resistances appeared to fall into three bands: (a) little apparent reduction in cyclic resistance for pumice contents up to 40%, (b) a reduction in cyclic resistance of approximately 20% at pumice contents of 80% and higher, and (c) a transitional zone. However, despite the lower cyclic resistance, the patterns of pore pressure generation and strain development did not appear to be affected by the amount of pumice in the soil mixture.

浮石土颗粒的特点是它们的水泡性质，这导致了重量轻，可破碎的颗粒，具有极其粗糙和棱角分明的表面纹理。这些特性赋予浮石土独特的工程特性，使其与更常见的硬颗粒材料不同，这使得工程师对评估液化的风险和潜在后果感兴趣。天然富浮石土壤含有不同数量的浮石；然而，目前还不清楚混合土中浮石的含量是如何改变这种行为的。通过一系列三轴试验，研究了浮石掺量对硬粒砂和浮石砂的循环阻力的影响。总体而言，循环阻力随浮石含量的增加而降低。此外，循环阻力表现为3个波段：(a)当浮石含量达到40%时，循环阻力下降幅度不大；(b)当浮石含量达到80%及以上时，循环阻力下降幅度约为20%；(c)处于过渡区。然而，尽管循环阻力较低，孔隙压力的产生和应变发展模式似乎不受混合土中浮石含量的影响。

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引用次数: 0

Load transfer behaviour of super long piles in multi-layer soft soil through field testing and numerical 3D FEM modelling 通过现场试验和三维有限元数值模拟研究了多层软土地基超长桩的荷载传递特性

IF 3.3 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

Soils and Foundations

Pub Date : 2025-05-23 DOI: 10.1016/j.sandf.2025.101627

Thoi Huu Tra , Thanh T. Nguyen , Thien Q. Huynh , Tatsuya Ishikawa

The load transfer mechanism of pile foundation has received considerable attention over the years, the simultaneous responses that skin friction and base resistances of super-long piles (length L > 60 m) can have in complex soft soil, however, still need greater understanding. This study employs 3D-finite element (FE) analysis incorporating virtual interface elements to simulate the mobilised skin friction and plastic failure (slippage) of pile under ultimate loading. Static pile load tests on 4 different long and large bored piles (1–1.5 m in diameter and 70–80 m in length) embedded in the soft soil region of Mekong Delta are studied in detail through extensive instrumentation along the piles. The results are then used to not only explore load-transfer process, but also validate numerical modelling through a comprehensive process combining multiple-soil layers and −loading stages. The coupled experimental (field) − numerical results reveal the predominant contribution of skin friction exceeding 90 % of the entire bearing capacity before a drop with swift rise in base resistance when reaching a critical condition (displacement s_h > 25 mm and load pressure p > 14,000 kPa). The ratio of active skin friction is defined to assess the simultaneous variation of skin friction at different depths, featuring the role of pile length on the mobilisation of skin friction. The study also proposes a novel dynamic method to calculate the strength reduction factor, R_i, based on fundamental soil and load parameters, giving a vital means to advancing the use of interface elements when modelling pile foundation in soft soil.

近年来，桩基荷载传递机制受到了广泛的关注，超长桩(长度L >；然而，在复杂的软土中，60 m)可以有更多的了解。本研究采用三维有限元（FE）分析，结合虚拟界面单元，模拟桩在极限荷载作用下的动摩和塑性破坏（滑移）。在湄公河三角洲软土地基地区，对4根直径1 ~ 1.5 m、长度70 ~ 80 m的大型钻孔灌注桩进行了静桩荷载试验研究。然后，研究结果不仅用于探索荷载传递过程，而且通过结合多个土层和加载阶段的综合过程验证数值模拟。耦合实验（场）-数值结果表明，在达到临界条件(位移sh >；25mm及负载压力p >；14000 kPa)。定义主动摩阻力比，以评价不同深度处摩阻力的同时变化，体现桩长对摩阻力调动的作用。本文还提出了一种基于基本土体和荷载参数计算强度折减系数Ri的动态方法，为在软土地基桩基础建模中推广界面单元的应用提供了重要手段。

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引用次数: 0

Hollow cylindrical torsional shear test simulating stress history of sand compaction pile work history 空心圆柱扭剪试验模拟砂压桩工作历程的应力历程

IF 3.3 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

Soils and Foundations

Pub Date : 2025-05-22 DOI: 10.1016/j.sandf.2025.101628

Hiroshi Yabe , Junichi Koseki

The Sand Compaction Pile (SCP) method is a widely utilized ground improvement technology that enhances the density of the ground by constructing sand piles through penetration and repeated withdrawal/re-driving of a casing pipe. This method is the most widely used liquefaction countermeasure method in Japan.

While the improvement effect of SCP is predominantly attributed to the resultant increase in soil density, recent studies have suggested that the stress history (such as increased lateral pressure and shear history) induced during the SCP work process also contributes significantly to its effectiveness. In order to more accurately reproduce the behavior of the ground during the construction of Sand Piles, the stress history simulating the SCP work process was applied to specimens in hollow cylindrical torsional shear tests, and the effects of the stress history were observed.

The specimens were initially consolidated with a lateral stress ratio of 0.5 (K₀ = 0.5). Subsequently, a stress history including increased lateral stress and cyclic shear stress was applied. Finally, liquefaction resistance was assessed through cyclic loading.

After applying the stress history, an increase in liquefaction resistance was observed in these specimens. This increase was larger than that of specimens subjected only to a lateral stress increase without the shear stress history. This increasing trend persisted even after the lateral stress was reduced following the application of stress history.

Finally, these test results were analyzed to assess the impact of stress history on liquefaction resistance by comparing them with the relationship between relative density and the liquefaction resistance.

砂压桩法（SCP）是一种广泛应用的地基改善技术，它通过钻穿和反复拔/再钻套管来建造砂桩，以提高地基密度。该方法是日本国内应用最广泛的液化对策方法。虽然SCP的改善效果主要归因于由此导致的土壤密度的增加，但最近的研究表明，SCP工作过程中引起的应力历史（如增加的侧压力和剪切历史）也对其效果起着重要作用。为了更准确地再现砂桩施工过程中的地基行为，将模拟SCP工作过程的应力历史应用于空心柱扭剪试验试件，观察应力历史对砂桩施工过程的影响。试件初始固结时，侧向应力比为0.5 （K0 = 0.5）。随后，应用应力史，包括增加的侧向应力和循环剪切应力。最后，通过循环加载对液化抗力进行了评估。施加应力历史后，观察到这些试样的液化阻力增加。这一增幅大于仅受侧向应力增加而不受剪应力历史影响的试件。即使在应用应力历史后降低了侧向应力，这种增加趋势仍然存在。最后对试验结果进行分析，并与相对密度与液化阻力的关系进行比较，评价应力历史对液化阻力的影响。

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引用次数: 0

Deformation characteristics and seepage mechanism of fractured rock mass under triaxial compression process 裂隙岩体三轴压缩变形特征及渗流机理

IF 3.3 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

Soils and Foundations

Pub Date : 2025-05-22 DOI: 10.1016/j.sandf.2025.101630

Jilu Zhang , Xiaohan Zhou , Xinrong Liu , Yang Kong , Bin Xu , Lojain Suliman

Understanding the gas seepage characteristics within fractured rock masses is of great significance for the prediction and prevention of hazardous gases in underground engineering. The formation is actually under a triaxial non-uniform stress state as a result of geological tectonic forces. Few studies on gas seepage take into account various stress situations. In this study, the flow characteristics of precast fractured rock masses were investigated through laboratory triaxial tests. The research results show that the volume strain of precast fracture changes from expansion to contraction with the decrease of the fracture angle under axial load. The fracture permeability decreases with the increase of axial strain before rock mass failure. After failure, the increase in permeability is not only related to the confining pressure and fracture angle but also has a significant correlation with the failure mode. Considering the triaxial non-uniform stress state, a coupled calculation model for seepage-stress-damage was established, and the calculation method was verified to effectively reflect the deformation and seepage characteristics of fractures. The lateral force on the fracture surface mainly causes the permeability of precast fractures to increase, and the increase extent of fracture permeability is negatively correlated with the fracture angle and elastic modulus.

了解裂隙岩体内气体渗流特征对地下工程有害气体的预测和防治具有重要意义。由于地质构造力的作用，该地层实际上处于三轴非均匀应力状态。很少有关于气体渗流的研究考虑到各种应力情况。本文通过室内三轴试验研究了预制裂隙岩体的流动特性。研究结果表明：在轴向载荷作用下，随着断裂角度的减小，预制构件的体应变由膨胀变为收缩；岩体破坏前，裂隙渗透率随轴向应变的增大而减小。破坏后渗透率的增加不仅与围压、破裂角有关，还与破坏模式有显著的相关性。考虑三轴非均匀应力状态，建立了渗流-应力-损伤耦合计算模型，并验证了该计算方法能有效反映裂隙变形和渗流特征。断裂面上的侧向力主要导致预制裂缝渗透性增加，裂缝渗透性增加的程度与断裂角度和弹性模量呈负相关。

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引用次数: 0

Stochastic estimation of soil hydraulic conductivity utilizing self-organizing map method 基于自组织图法的土壤导电性随机估计

IF 3.3 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

Soils and Foundations

Pub Date : 2025-05-21 DOI: 10.1016/j.sandf.2025.101601

Kyeongmo Koo, Hyunki Kim

This study proposes an unsupervised Self-Organizing Map (SOM) approach to enhance saturated hydraulic conductivity (k_sat) estimation. Using the extensive FLSOIL database of 6,487 soil samples from Florida, the SOM-based k_sat estimation model is optimized based on map size and feature selection, then compared with seven empirical equations and three supervised machine learning models. Unlike the other methods, the SOM-based approach provides a probabilistic distribution of k_sat, enabling reliability-based design-value determination. Moreover, refining input features particularly by including specific surface area and Kozeny–Carman derived formulas improves accuracy and mitigates bias by the model features, especially in fine-grained soils.

本研究提出一种无监督自组织图（SOM）方法来提高饱和水力导电性（ksat）的估计。利用佛罗里达州FLSOIL数据库中6,487个土壤样本，基于地图大小和特征选择对基于som的ksat估计模型进行了优化，并与7个经验方程和3个监督机器学习模型进行了比较。与其他方法不同，基于som的方法提供了ksat的概率分布，从而实现了基于可靠性的设计值确定。此外，细化输入特征，特别是包括比表面积和Kozeny-Carman推导公式，提高了准确性，减轻了模型特征的偏差，特别是在细粒土壤中。

引用次数: 0

Effects of flocculants on in–situ recycling potential of waste EPB shield muck with residual foams 絮凝剂对含残余泡沫的EPB废渣原位回收潜力的影响

IF 3.3 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

Soils and Foundations

Pub Date : 2025-05-16 DOI: 10.1016/j.sandf.2025.101625

Yao Lu , Ming Huang , Jim S. Shiau , Fengwen Lai , Liqian Peng

The in–situ recycling technique offers a promising solution for the efficient management of the escalating volumes of waste muck or slurry generated during shield tunneling. While foam is extensively utilized for soil conditioning in earth pressure balance (EPB) tunneling, the effects of organic and inorganic flocculants on the in–situ recycling potential of waste EPB shield muck containing residual foams remain underexplored. To bridge this gap, laboratory experiments were conducted using four flocculants: cationic polyacrylamide (CPAM), nonionic polyacrylamide (NPAM), anionic polyacrylamide (APAM), and polyaluminum chloride (PACL), with an enhanced flocculation and press–filtration apparatus. The defoaming–flocculation–dewatering behavior of waste EPB shield muck was systematically investigated by evaluating key parameters, including residual foam height, defoaming ratio, antifoaming ratio, total suspended solids, turbidity, moisture content, and zeta potential, while accounting for both muck dry mass and fines content. Moreover, the microscopic structure of flocculates and filter cakes was characterized using nanoparticle size analysis and scanning electron microscopy. The experimental results reveal that CPAM exhibits constrained flocculation and dewatering efficiency, primarily attributed to diminished charge neutralization resulting from residual anionic surfactants. In contrast, PACL demonstrates superior dewatering performance compared to NPAM and APAM, but exhibits the lowest flocculation and foam–suppression efficiency. Additionally, a consistent linear negative correlation is identified between the flocculation and dewatering indices of EPB shield muck, independent of the flocculant type, whether organic or inorganic.

就地回收技术为有效管理盾构隧道施工过程中产生的不断增加的废渣或泥浆量提供了一个很有前途的解决方案。虽然泡沫被广泛用于土压平衡（EPB）隧道的土壤调节，但有机和无机絮凝剂对含残余泡沫的EPB盾构垃圾原位回收潜力的影响尚未得到充分研究。为了弥补这一空白，利用阳离子聚丙烯酰胺（CPAM）、非离子聚丙烯酰胺（NPAM）、阴离子聚丙烯酰胺（APAM）和聚氯化铝（PACL）四种絮凝剂进行了实验室实验，并采用了增强絮凝和压滤装置。在兼顾渣土干质量和细粒含量的前提下，通过评价残余泡沫高度、消泡比、消泡比、总悬浮物、浊度、含水率、zeta电位等关键参数，系统研究了EPB盾构渣土的消泡-絮凝-脱水行为。利用纳米粒度分析和扫描电镜对絮凝剂和滤饼的微观结构进行了表征。实验结果表明，CPAM表现出有限的絮凝和脱水效率，主要是由于残留的阴离子表面活性剂减少了电荷中和作用。PACL的脱水性能优于NPAM和APAM，但絮凝抑泡效果较差。此外，EPB屏蔽渣的絮凝与脱水指标之间存在线性负相关关系，与絮凝剂类型（有机或无机）无关。

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引用次数: 0

Performance of screw piles in bio-stabilized slope based on field monitoring and finite element modelling 基于现场监测和有限元模拟的生物稳定边坡螺旋桩性能研究

IF 3.3 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

Soils and Foundations

Pub Date : 2025-05-05 DOI: 10.1016/j.sandf.2025.101626

Apiniti Jotisankasa , Korakot Tanyacharoen , Susit Chaiprakaikeow , Washirawat Praphatsorn , Sony Pramusandi , Avishek Shrestha , Satoshi Nishimura

A novel slope stabilization technique was recently developed incorporating screw piles with vegetated flapped soilbags. These screw piles are subjected to lateral stress from soil slope and their deformation can be difficult to quantify, given the fluctuating pore-water pressure and heterogeneous soil conditions. This study proposes the use of in-situ spectral analysis of surface waves (SASW) test to estimate the small-strain soil stiffness which can then be factored to calculate the lateral deformation of the pile in finite element modelling based on prescribed pore-water pressure change. A case of bioengineered slope in Kanchanaburi province, Western Thailand was studied, involving field monitoring of pile head tilt, pore-water pressure, suction, and soil moisture over one year. The findings revealed pile head tilt of up to 0.2 degrees in response to rainfall and rise in pore-water pressure and soil moisture over one year period. A series of finite element modelling were performed using factored shear moduli from in-situ SASW test and the monitored pore-water pressure variation to reproduce the amount of pile head tilting as observed in the field during one year. It was revealed that by assuming operational shear modulus ranging between 0.0075 and 0.01 times small-strain soil stiffness, a satisfactory agreement was obtained between field measurement and analysis of pile movement. This findings provides a basis for further studies on performance of bioengineered slope utilizing screw piles.

近年来发展了一种新型的边坡稳定技术，将螺旋桩与植物扑翼土袋相结合。考虑到孔隙水压力的波动和非均质土壤条件，这些螺旋桩受到来自土坡的侧向应力，其变形难以量化。本研究提出使用原位表面波谱分析（SASW）试验来估算小应变土刚度，然后根据规定的孔隙水压力变化，在有限元建模中计算桩的侧向变形。以泰国西部北碧府的一个生物工程边坡为例，进行了为期一年的桩顶倾斜度、孔隙水压力、吸力和土壤湿度的现场监测。研究结果显示，在一年的时间里，随着降雨、孔隙水压力和土壤湿度的上升，桩顶的倾斜度可达0.2度。利用现场SASW试验的剪切模量和监测的孔隙水压力变化进行了一系列有限元建模，以再现一年内现场观察到的桩头倾斜量。计算结果表明，假设操作剪切模量为小应变土刚度的0.0075 ~ 0.01倍，现场实测结果与桩身运动分析结果吻合较好。研究结果为进一步研究螺旋桩生物工程边坡的性能奠定了基础。

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引用次数: 0