Geomechanics for Energy and the Environment最新文献_第9页

Unified models for water permeability in hydrate-bearing sandy soil considering pore morphology evolution 考虑孔隙形态演化的含水砂土透水性统一模型

IF 3.3 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-07-14 DOI: 10.1016/j.gete.2025.100717

Lin-Yong Cui , Chao Zhou , Sheng Dai

The water permeability of hydrate-bearing sediments is of paramount importance for assessing the exploitation efficiency of methane hydrate from reservoirs. It is largely influenced by the interrelated factors of hydrate morphology and saturation. Experimental results revealed that as hydrate saturation increases, the pore morphology shifts from primarily grain-coating to predominantly pore-filling, but this coupling effect between hydrate morphology and saturation on water permeability is often overlooked in existing models. This study aims to model the water permeability of hydrate-bearing sandy soils, considering the evolution of pore morphology with changing hydrate saturation. An eccentric annulus is used to depict the pore structure of pore-filling hydrate, in contrast to the conventional unrealistic concentric annulus geometry. Two new models to describe water relative permeability were derived, each incorporating only a single parameter, assuming that grain-coating and pore-filling hydrates grow at different rates either sequentially or simultaneously. These models were validated using a dataset comprising 29 hydrate-bearing soils, with the hydrate saturations ranging from approximately 0 to 0.9. Comparison between model predictions and experimental data confirmed the good performance of both water permeability models, with low RMSE, MAE and GMV values of around 0.05, 0.03 and 1.28, respectively. Both models were further improved by correlating the two parameters with porosity data, which could ensure a rapid estimation of relative permeability based solely on porosity data without requiring any fitting parameters. Results in this study provide a novel perspective for understanding the impact of hydrate evolution on permeability reduction in hydrate-bearing soils.

含水沉积层的渗透率是评价储层甲烷水合物开发效率的重要指标。这在很大程度上受水合物形态和饱和度等相关因素的影响。实验结果表明，随着水合物饱和度的增加，孔隙形态由以颗粒包覆为主向以孔隙填充为主转变，但现有模型往往忽略了水合物形态和饱和度对渗透率的耦合作用。考虑含水砂土孔隙形态随含水饱和度变化的演化规律，建立含水砂土渗透性模型。采用偏心环空来描述充孔水合物的孔隙结构，与传统的不切实际的同心环空几何结构形成对比。推导了两个描述水相对渗透率的新模型，每个模型都只包含一个参数，假设颗粒包覆和孔隙填充水合物以不同的速率依次或同时增长。使用包含29种含水土壤的数据集对这些模型进行了验证，这些含水土壤的含水饱和度范围约为0至0.9。通过模型预测与实验数据的对比，验证了两种渗透率模型的良好性能，均具有较低的RMSE、MAE和GMV值，分别在0.05、0.03和1.28左右。通过将两个参数与孔隙度数据相关联，进一步改进了这两个模型，可以确保仅根据孔隙度数据快速估计相对渗透率，而不需要任何拟合参数。研究结果为理解水合物演化对含水土壤渗透降低的影响提供了新的视角。

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引用次数: 0

Centrifuge modelling of energy geostructures in soil: A review 土中能量土工结构的离心模拟研究进展

IF 3.3 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-07-14 DOI: 10.1016/j.gete.2025.100719

Rui Zhao , Cong Shao , Jonathan Adam Knappett , Anthony Kwan Leung , Teng Liang , Liangtong Zhan , Yunmin Chen

Energy geostructures integrate heat exchange pipes of ground source heat pump systems within traditional underground structures, serving the dual purpose of extracting geothermal energy and supporting above-ground structures. The interaction between geothermal structures and soil involves heat transfer, pore pressure evolution and soil skeleton deformation, exhibiting a coupled thermo-hydro-mechanical response. Although detailed numerical and analytical models have been developed to analyze the thermo-hydro-mechanical behaviour of energy geostructures in soil, significant challenges remain in validating this coupled response. Centrifuge modelling provides prototype confining stresses in reduced-scale models, providing an alternative to field measurements with more controllable conditions and at lower cost. This paper reviews the current state of the art of centrifuge modelling of energy geostructure–soil interaction, with a particular focus on (i) scaling laws; (ii) evaluations of existing heating and cooling systems; (iii) soil modelling, including material selection and model preparation; and (iv) scale modelling of energy geostructural elements. Each section emphasizes the challenges of centrifuge modelling and presents identified solutions to these challenges. Finally, the prospect for future studies is discussed, highlighting the potential to enhance understanding of the underlying mechanisms controlling thermo-hydro-mechanical behaviour of geothermal structures in soil.

能源土工构筑物将地源热泵系统的换热管道集成在传统地下构筑物内，起到提取地热能和支撑地上构筑物的双重作用。地热构造与土壤的相互作用涉及传热、孔隙压力演化和土壤骨架变形，表现出热-水-力耦合响应。尽管已经开发了详细的数值和分析模型来分析土壤中能量土工结构的热-水-力学行为，但在验证这种耦合响应方面仍然存在重大挑战。离心机建模提供了缩小比例模型的原型围应力，为现场测量提供了更可控条件和更低成本的替代方案。本文回顾了能量土工结构-土壤相互作用的离心模型的现状，特别关注(i)标度定律；（ii）评估现有的加热及冷却系统；（iii）土壤建模，包括材料选择和模型准备；（四）能量土工结构单元的尺度建模。每个部分都强调了离心机建模的挑战，并提出了应对这些挑战的确定解决方案。最后，讨论了未来研究的前景，强调了加强对控制土壤地热结构热-水-力学行为的潜在机制的理解的潜力。

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引用次数: 0

Effect of particle size on mechanical properties of bio-cemented sand using enzyme-induced calcite precipitation 粒径对酶促方解石沉淀生物胶结砂力学性能的影响

IF 3.3 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-07-14 DOI: 10.1016/j.gete.2025.100718

Qi-Wu Jiang , Ming Huang , Kai Xu , Ming-Juan Cui , Gui-Xiao Jin , Xiao-Ping Zhang

Enzyme-induced carbonate precipitation (EICP) has emerged as a promising eco-friendly biotechnology for soil stabilization. The mechanical properties of bio-cemented sands are largely determined by particle size characteristics. However, the influencing mechanism of particle size characteristics on bio-cemented sands remains unclear. In this study, a series of bio-cemented sand column tests were conducted to explore particle size effects. Different particle size (coarse, medium, fine) were treated with different numbers of cycles (6, 8, 10). Multiple key parameters of the bio-cemented sands were measured, including permeability, unconfined compressive strength (UCS), calcium carbonate content (CCC), and wave velocity. The SEM imaging technique was employed to demonstrate the impact of sand particle size on cementation effect in bio-cemented specimens. Linear relationships were established between wave velocity, permeability, UCS, and CCC with different particle size. The results showed that particle size significantly influences the CCC, UCS, wave velocity, and permeability of EICP-treated sands. Medium-grained sands exhibited the highest UCS and wave velocity under EICP treatment. This is attributed to medium sands can achieve a good balance between the efficiency of pore-filling by calcium carbonate crystals and the infiltration of the EICP solution. Fine sands suffered from inhomogeneous CaCO₃ distribution due to the clogging of pores, which hindered the uniform penetration of the EICP solution. Coarse sands showed limited cementation owing to oversized pores, which impeded the effective interparticle bonding mediated by precipitated calcium carbonate. These findings establish particle size thresholds for EICP efficacy, providing critical guidelines for particle size selection in field-scale biocementation projects.

酶诱导碳酸盐降水（EICP）是一种很有前途的生态友好型土壤稳定生物技术。生物胶结砂的力学性能在很大程度上取决于粒径特征。然而，粒径特性对生物胶结砂的影响机理尚不清楚。在本研究中，进行了一系列生物胶结砂柱试验，以探索粒径效应。不同粒度（粗、中、细）采用不同循环次数（6、8、10）处理。测量了生物胶结砂的多个关键参数，包括渗透率、无侧限抗压强度（UCS）、碳酸钙含量（CCC）和波速。采用扫描电镜（SEM）成像技术研究了生物胶结试样中砂粒尺寸对胶结效果的影响。不同粒径下波速、渗透率、UCS、CCC均呈线性关系。结果表明，颗粒尺寸对eicp处理砂的CCC、UCS、波速和渗透率有显著影响。在EICP处理下，中粒砂的UCS和波速最高。这是由于中砂可以很好地平衡碳酸钙晶体的孔隙填充效率和EICP溶液的渗透。细砂由于孔隙堵塞导致CaCO3分布不均匀，阻碍了EICP溶液的均匀渗透。粗砂由于孔隙过大，胶结作用有限，阻碍了沉淀碳酸钙介导的颗粒间有效结合。这些发现建立了EICP效果的粒径阈值，为现场规模生物胶结项目的粒径选择提供了重要指导。

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引用次数: 0

Thermal influence zone of energy tunnels in sandy soils under the hydrostatic condition 静水条件下砂土能量隧道热影响区

IF 3.3 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-07-13 DOI: 10.1016/j.gete.2025.100716

Alaaeldin Magdy , Alice Di Donna , Hussein Mroueh

Energy geostructures are more and more considered as a possible solution to cover heating and cooling needs. They function according to the principle of shallow geothermal energy, exchanging heat with the ground. This results in a zone underground where the temperature of the ground is affected by the presence of the geothermal system, which is called thermal influence zone. As the number of energy geostructures increases, determining their thermal influence zone becomes crucial, especially in environments where adjacent energy geostructures or other geothermal systems coexist. Indeed, avoid or minimize the overlap between the thermal influence zones of different geothermal installations is important to ensure their efficiency. This study investigates the effects of groundwater level, thermal operation period, and ground permeability, in both heating and cooling modes, on the thermal influence zone generated around an energy tunnel. The results indicate that the thermal induced change in groundwater density and viscosity due to geothermal operations generates groundwater circular flows. These flows play a major role in shaping the thermal influence zone. In the heating mode (winter), when the groundwater is within the vicinity of the tunnel, i.e., above, at or just below the tunnel, the thermal influence zone takes an oval shape elongated below the tunnel invert. In the cooling mode (summer), the thermal influence zone does not follow a specific shape, and it is remarkably changed by the groundwater level. For instance, when the groundwater level is shallow, the thermal influence zone extends significantly upward, potentially overlapping with the surface layer affected by atmospheric air temperature. However, when the groundwater level at the tunnel centreline, the thermal influence zone takes a horizontal oval shape, which might interfere with adjacent similar installations. The expansion of the thermal influence zone is highly dependent on the operation duration. In winter, the downward elongation after 6 months operation reaches around 1.5 times that after 3 months.

能源土工结构越来越被认为是满足供暖和制冷需求的可能解决方案。它们根据浅层地热能原理工作，与地面交换热量。这就产生了地下的一个区域，在这个区域里，地面的温度受到地热系统的影响，这个区域被称为热影响区。随着能源土工结构数量的增加，确定其热影响区变得至关重要，特别是在邻近能源土工结构或其他地热系统共存的环境中。事实上，避免或尽量减少不同地热装置的热影响区之间的重叠对于确保其效率非常重要。研究了地下水位、热力运行周期和地下渗透率对能量隧道周边热影响区的影响。结果表明，地热开采引起的地下水密度和粘度的热致变化产生了地下水循环流动。这些气流在形成热影响区方面起主要作用。在采暖模式下（冬季），当地下水处于隧道附近，即隧道上方、下方或下方时，热影响区在隧道仰拱下方呈椭圆形拉长。在降温模式下（夏季），热影响区不遵循特定的形状，受地下水位的影响变化显著。例如，当地下水位较浅时，热影响区明显向上延伸，可能与受大气温度影响的表层重叠。然而，当地下水位在隧道中心线时，热影响区呈水平椭圆形，可能会干扰邻近的类似设施。热影响区的扩展高度依赖于运行时间。冬季手术6个月后的下伸率达到3个月后的1.5倍左右。

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引用次数: 0

Coupled hydro–mechanical simulation of the interaction between adjacent lined rock caverns subject to internal gas pressurisation 内部气体增压作用下相邻衬岩洞室相互作用的水-力耦合模拟

IF 3.3 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-07-10 DOI: 10.1016/j.gete.2025.100701

Chenxi Zhao , Zixin Zhang , Qinghua Lei

We develop a two-dimensional (2D) fully-coupled hydro–mechanical model to study the performance of gas pressurised adjacent lined rock caverns (LRCs) in water-saturated fractured rock masses. The 2D model represents the horizontal cross-section of LRCs and their surrounding rock masses subjected to various in-situ stress and pore pressure conditions. We explore different LRC operational scenarios, including a double cavern configuration with one cavern or both caverns under gas filling. We analyse the evolution of damage in both the rock mass and concrete lining, as well as tangential strain in the concrete and steel linings. Our simulation results indicate that damage in the rock mass develops in the form of wing cracks from pre-existing fracture tips while damage in the concrete lining is primarily induced by tensile cracking under cavern pressurisation. Pore pressure varies significantly in the surrounding rock mass during the cavern pressurisation, leading to pronounced damages. Among the different operational conditions explored in this study, we find that the configuration with one cavern under pressurisation while the other at a low initial/residual gas pressure can reach a higher gas infilling pressure, due to the higher compliance of the system. The insights gained from our study have important implications for optimising the design and performance of LRCs for sustainable underground hydrogen storage.

我们建立了一个二维（2D）全耦合的水力学模型来研究饱和水裂隙岩体中气体加压相邻衬砌岩洞（lrc）的性能。二维模型表示在不同地应力和孔隙压力条件下lrc及其围岩的水平截面。我们探索了不同的LRC操作场景，包括在气体填充下的双洞室配置和一个洞室或两个洞室。我们分析了岩体和混凝土衬砌的损伤演变，以及混凝土和钢衬砌的切向应变。我们的模拟结果表明，岩体的损伤以先前存在的断裂尖端的翼状裂纹的形式发展，而混凝土衬砌的损伤主要是由洞室加压下的拉伸开裂引起的。在硐室加压过程中，围岩孔隙压力变化较大，造成了明显的破坏。在本研究探索的不同运行条件中，我们发现，由于系统的顺应性更高，一个洞室处于加压状态，另一个洞室处于较低的初始/残余气体压力下，可以达到较高的气体充注压力。从我们的研究中获得的见解对于优化lrc的设计和性能以实现可持续的地下储氢具有重要意义。

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引用次数: 0

Hydromechanical simulation of argillaceous rocks: From laboratory tests to drift excavation 泥质岩石的流体力学模拟：从实验室试验到进路开挖

IF 3.3 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-07-09 DOI: 10.1016/j.gete.2025.100714

Davood Yazdani Cherati , Jean Vaunat , Antonio Gens Solé , Carlos Plua , Minh Ngoc Vu , Gilles Armand

This study aims to evaluate the role of the pre-peak hardening regime in an elasto- viscoplastic model for argillaceous rocks, called the argillite model, use the model to replicate the hydromechanical response of argillaceous rocks observed in both laboratory and field tests, and investigate the interactions between excavation supports and these geomaterials. Initially, the impacts of the pre-peak strain hardening regime on behavior of argillaceous rocks are investigated through modeling a series of theoretical biaxial tests. Afterward, the model is validated by simulating biaxial and triaxial tests conducted on Beaucaire marl and Callovo-Oxfordian (COx) clay samples, respectively. Additionally, the role of the hardening regime in capturing the dependence of strain at peak strength on confining pressure is demonstrated using the triaxial models. Next, the effects of the hardening regime on the hydromechanical response of argillaceous rocks to drift excavations are demonstrated by modeling GCS drift, excavated within the Meuse/Haute-Marne Underground Research Laboratory (MHM URL). Subsequently, the argillite model is employed to simulate three other supported and unsupported drifts, excavated within the MHM URL. Finally, the long-term failure pattern of the concrete lining is predicted. Results indicate that incorporating the hardening regime and support effects can significantly enhance the accuracy of the model predictions.

本研究旨在评估峰值前硬化机制在泥岩弹粘塑性模型（即泥岩模型）中的作用，利用该模型复制实验室和现场试验中观察到的泥岩流体力学响应，并研究开挖支架与这些岩土材料之间的相互作用。首先，通过模拟一系列理论双轴试验，研究了峰前应变硬化对泥质岩石行为的影响。随后，分别在Beaucaire泥灰岩和Callovo-Oxfordian （COx）粘土样品上进行了双轴和三轴模拟试验，对模型进行了验证。此外，使用三轴模型证明了硬化机制在捕获峰值强度下应变对围压的依赖中的作用。接下来，通过模拟在默兹/上马恩地下研究实验室（MHM URL）挖掘的GCS漂移，验证了硬化机制对泥质岩石对漂移开挖的水力学响应的影响。随后，利用泥质岩模型模拟了在MHM URL内开挖的另外三个有支撑和无支撑的巷道。最后，对混凝土衬砌的长期破坏模式进行了预测。结果表明，考虑硬化机制和支撑效应可以显著提高模型预测的准确性。

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引用次数: 0

Stability analysis of compressed air energy storage in underground space: A comparative research of coal mine roadway and salt cavern 地下空间压缩空气储能稳定性分析——以煤矿巷道与盐洞为例

IF 3.3 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-07-08 DOI: 10.1016/j.gete.2025.100715

Jinyang Fan , Pengyu Guo , Yifan Wang , Zongze Li , Yang Zou , Deyi Jiang , Daniel Nelias

The application of Compressed Air Energy Storage (CAES) in large-scale projects offers a promising solution for mitigating fluctuations in renewable energy generation. Focusing on the CAES project in Yungang coal mine, Datong, Shanxi, this study qualitatively and quantitatively investigated the impact of creep and cyclic loading on the roadway under various CAES operating frequencies. Stability indicators for Compressed Air Energy Storage Roadways (CAES-R), including displacement contours, roof subsidence, volume shrinkage, etc., were compared at different CAES operating frequencies, and the stability of CAES-R was compared to salt cavern CAES. Results reveal that higher CAES operating frequencies correspond to lower roadway deformation and plastic damage. After ten years of simulation with daily operation frequency, roof subsidence reaches approximately 20 mm, with a volume shrinkage of 0.76 %. Under the reduced frequency of once every 10 days, roof subsidence reaches 33 mm and volume shrinkage 1.05 % after ten years. Junction sections exhibited greater deformation than non-junction sections, demonstrating higher susceptibility to structural failure. Most deformation and damage occur rapidly during early operation stages, accumulating more slowly thereafter. A novel comparative analysis between CAES-R and traditional salt cavern CAES indicates CAES-R reservoirs exhibit significantly lower volumetric shrinkage rates and smaller plastic zones than the comparative study. Taking various factors into consideration, CAES-R also has better prospects than salt cavern CAES. It should be noted that the general applicability of these findings requires further site-specific evaluation due to geological heterogeneity and operational constraints.

压缩空气储能（CAES）在大型项目中的应用为缓解可再生能源发电的波动提供了一个有前途的解决方案。以山西大同云岗煤矿CAES工程为研究对象，定性和定量研究了不同CAES工作频率下蠕变和循环荷载对巷道的影响。对比了不同CAES工作频率下压缩空气储能巷道（CAES- r）的位移轮廓、顶板沉陷、体积收缩等稳定性指标，并与盐洞CAES进行了稳定性对比。结果表明，CAES工作频率越高，巷道变形和塑性损伤越小。按日作业频率模拟10年后，顶板沉陷约20 mm，体积收缩率0.76 %。在每10天减少1次的频率下，10年后顶板沉陷33 mm，体积收缩率1.05 %。结截面比非结截面表现出更大的变形，表明对结构破坏的敏感性更高。大多数变形和损伤在操作初期迅速发生，此后积累较慢。一项新的对比分析表明，CAES- r与传统盐洞CAES相比，CAES- r储层表现出更低的体积收缩率和更小的塑性区。综合各方面因素，CAES- r也比盐洞CAES有更好的发展前景。应当指出，由于地质不均匀性和操作限制，这些发现的普遍适用性需要进一步对具体地点进行评价。

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引用次数: 0

Surface–subsurface flow effect on earthen dikes geomechanical stability during overtopping event 地表-地下流动对漫顶过程中土堤地质力学稳定性的影响

IF 3.3 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-07-03 DOI: 10.1016/j.gete.2025.100709

Nathan Delpierre, Hadrien Rattez, Sandra Soares-Frazão

Droughts and extreme precipitation events, exacerbated by climate change, are causing growing threats to earthen dams. The increasing frequency of extreme events, which were not always considered when these earthen structures were built means that these factors may not have been fully accounted for in their design. The risk of overtopping flow is therefore increased and the initial soil’s saturation level has a significant impact on the structure’s strength that should not be overlooked during the assessment of the dike risk of failure when overtopped. In this paper, we present a novel numerical framework that consists in a physically-based approach which allows to study the effects of combined surface–subsurface flows on the slope stability evolution, using an effective stress formulation for the mechanical analysis. The surface flows are described using a one-dimensional shallow-water equations solver and are coupled in a conservative way with the subsurface flow, through a two-dimensional Richards equation solver. The shear strength reduction method is employed, in combination with an effective stress approach, to assess the longitudinal and lateral slope safety factor evolution taking into account the pore-pressure and saturation degree changes in time during overtopping.

气候变化加剧了干旱和极端降水事件，对土坝造成了越来越大的威胁。这些土制建筑在建造时并不总是考虑到极端事件的日益频繁，这意味着这些因素在设计时可能没有充分考虑到。因此，溢流的风险增加，初始土的饱和水平对结构的强度有显著影响，这在堤防溢流破坏风险评估中不可忽视。在本文中，我们提出了一个新的数值框架，它包含在一个基于物理的方法中，允许研究地表-地下联合流动对边坡稳定性演变的影响，使用有效的应力公式进行力学分析。使用一维浅水方程求解器描述地表流动，并通过二维Richards方程求解器以保守方式与地下流动耦合。采用抗剪强度折减法，结合有效应力法，对考虑过顶过程中孔隙压力和饱和度随时间变化的边坡纵向和侧向安全系数演化进行了评价。

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引用次数: 0

Study on the fracture propagation rule of simultaneous fracturing under cyclic injection 循环注入条件下同时压裂裂缝扩展规律研究

IF 3.3 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-07-03 DOI: 10.1016/j.gete.2025.100711

Ge Zhu , Chuanli Wei , Jingna Liu

Simultaneous fracturing has emerged as a pivotal technology in unconventional oil and gas development, offering significant advantages in enhancing operational efficiency and reducing costs. However, plagued by stress shadow, non-uniform propagation of multiple fractures may occur during the operation, resulting in the stimulated reservoir volume (SRV) failing to meet the requirements. This study proposes an innovative scheme of utilizing cyclic injection to alleviate stress shadow. The dynamic stress generated by cyclic injection can complicate the interaction of multiple fractures during propagation, increasing the complexity of the fracture network. Furthermore, a numerical simulation model of multi-fracture propagation during simultaneous fracturing under cyclic injection was established using the extended finite element method (XFEM). The impact of the temporal modulation parameters governing cyclic injection scheme, including period, amplitude and phase, on the fracture propagation was discussed. Finally, an operational scheme was proposed in which different operating wells use distinct cyclic injection rates during simultaneous fracturing. The results reveal that cyclic injection scheme can significantly alleviate the fracture propagation disparities caused by stress shadow compared to conventional constant injection mode. The period, amplitude, and phase of cyclic injection rate exert critical control over fracture propagation morphology during simultaneous fracturing operations. Notably, the implementation of different cyclic injection schemes for various operating wells represents a deliberate attempt to alleviate stress shadow and improve fracture complexity. The research results can provide guidance for the field application of simultaneous fracturing and significantly contribute to improving the SRV.

同时压裂已成为非常规油气开发的关键技术，在提高作业效率和降低成本方面具有显著优势。然而，由于受应力阴影的影响，在作业过程中可能出现多条裂缝的不均匀扩展，导致增产储层体积（SRV）达不到要求。本研究提出了一种利用循环注射来缓解应力阴影的创新方案。循环注入产生的动应力会使多条裂缝在扩展过程中的相互作用复杂化，增加裂缝网络的复杂性。在此基础上，采用扩展有限元法（XFEM）建立了循环注入条件下同时压裂过程中多裂缝扩展的数值模拟模型。讨论了周期、振幅和相位等控制循环注入方案的时间调制参数对裂缝扩展的影响。最后，提出了不同作业井在同时压裂过程中使用不同循环注入速率的作业方案。结果表明，与常规恒注入相比，循环注入方案能显著缓解应力阴影引起的裂缝扩展差异。在同步压裂作业中，循环注入速率的周期、幅度和相位对裂缝扩展形态起着至关重要的控制作用。值得注意的是，针对不同的作业井实施不同的循环注入方案，表明了有意缓解应力阴影和提高裂缝复杂性的尝试。研究成果可为同时压裂的现场应用提供指导，对提高SRV具有重要意义。

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引用次数: 0

Temperature- and Displacement-Dependent Model for unsaturated Earth pressures behind thermo-active retaining walls 热活性挡土墙后非饱和土压力的温度和位移依赖模型

IF 3.3 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-07-03 DOI: 10.1016/j.gete.2025.100712

Ahmad Rajabian, Farshid Vahedifard

Earth pressures behind a thermo-active retaining wall can be influenced not only by the temperature-dependent response of the unsaturated backfill but also by the thermal expansion or contraction of the wall during the cooling and heating operations of a coupled heat pump. Such lateral deformations cause the unsaturated backfill to be placed in an intermediate passive or active state. In this study, an analytical framework is presented to compute the temperature- and displacement-dependent earth pressures of unsaturated soils behind embedded thermo-active retaining walls. The application of the proposed model is demonstrated by comparing its results with those from field-scale tests reported in the literature. A set of parametric studies is performed on a 6-m embedded thermo-active wall backfilled with three hypothetical soils (clay, silt, and sand) at 25 °C, 35 °C, and 45 °C. Further, unsaturated earth pressure profiles are generated for various thermally induced expansions and contractions during cooling and heating cycles. The results show that elevated temperatures decrease passive earth pressure and reduce the depth of tension cracks in at-rest and active states. Additionally, lateral wall expansion during the cooling cycle helps eliminate the tension zone. However, the heating cycle of the heat pump can be critical, as it leads to lateral contraction of the wall, thereby developing a tension-cracked zone, which can negatively affect the system’s efficacy. The presented framework is a useful tool for forensic studies as well as assessing the serviceability of embedded thermo-active retaining walls under working stress conditions by linking geotechnical and structural aspects.

热工挡土墙背后的土压力不仅会受到非饱和回填体温度相关响应的影响，还会受到耦合热泵制冷和加热过程中墙体热膨胀或收缩的影响。这种侧向变形使非饱和充填体处于被动或主动的中间状态。在本研究中，提出了一个分析框架来计算嵌入式热活性挡土墙后非饱和土的温度和位移相关土压力。通过将该模型的结果与文献中报道的现场规模试验结果进行比较，证明了该模型的应用。在25 °C， 35 °C和45 °C的条件下，对6米嵌入式热活性墙进行了一组参数研究，回填了三种假设的土壤（粘土，淤泥和沙子）。此外，在冷却和加热循环过程中，产生了各种热致膨胀和收缩的非饱和土压力剖面。结果表明：温度升高使被动土压力减小，静息状态和活动状态下拉裂缝深度减小；此外，在冷却循环期间，侧壁膨胀有助于消除张力区。然而，热泵的加热循环可能是至关重要的，因为它会导致墙体的侧向收缩，从而形成一个拉伸裂纹区，这可能会对系统的功效产生负面影响。所提出的框架是法医研究的有用工具，以及通过连接岩土和结构方面来评估工作应力条件下嵌入式热活性挡土墙的可用性。

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