Geomechanics for Energy and the Environment最新文献_第5页

Mechanism of gas seepage enhancement based on the evolution of micro-pores and energy dissipation in coal under dynamic load 动载下煤体微孔演化与能量耗散的瓦斯渗流强化机理

IF 3.7 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-10-31 DOI: 10.1016/j.gete.2025.100762

Di He , Shugang Li , Xiangguo Kong , Haifei Lin , Yankun Ma , Yuchu Cai

During the development of deep coalbed methane resources, the impact caused by mining disturbance has a significant effect on the evolution of coal pore-fracture and permeability characteristics. Revealing the damage mechanism and gas seepage law of coal in the mining process can provide important basis for the efficient exploitation of coalbed methane. Dynamic impact tests were conducted using the Split Hopkinson Pressure Bar (SHPB) testing system, the T₂ relaxation spectrum and permeability of the impacted coal were measured, respectively. The evolution of pore damage and permeability in coal samples was analyzed from the perspective of energy dissipation. The results showed that as impact pressure increases, adsorption and seepage pores successively dominate the evolutionary process, and the pore fractal dimension of coal samples first increases and then decreases. Magnetic Resonance Imaging (MRI) images reveal obvious linear concentrated damage zones, and these zones lead to the overall evolution of pore structure from point-like dispersion to complex linear interweaving. The permeability of coal samples increases as the impact pressure increases. Under the same impact pressure conditions, the permeability decreases exponentially with an increase in gas pressure. The dissipation energy density and damage variable of coal samples both increase exponentially with the increase of impact pressure. Impact disturbances significantly affect the expansion of pores and fractures in coal. As the damage variable increases, both the porosity and permeability increment of the coal sample exhibit a linear increasing trend. As the extraction time of the test working face increases, the energy of microseismic events and the absolute gas emission show an increasing trend. This indicates that the effect of impact wave causes the gas seepage channel of coal expand, and the permeability enhancement effect is significant.

在深部煤层气资源开发过程中，采动扰动对煤层孔隙-裂隙及渗透率特征的演化具有重要影响。揭示煤在开采过程中的破坏机理和瓦斯渗流规律，可为煤层气的高效开采提供重要依据。采用分离式霍普金森压杆（SHPB）试验系统进行动态冲击试验，分别测量了冲击煤的T2弛豫谱和渗透率。从能量耗散的角度分析了煤样孔隙损伤和渗透率的演化过程。结果表明：随着冲击压力的增大，吸附孔和渗流孔先后主导演化过程，煤样孔隙分形维数先增大后减小；核磁共振成像（MRI）图像显示出明显的线性集中损伤区，这些损伤区导致孔隙结构整体由点状分散向复杂的线性交织演变。煤样渗透率随冲击压力的增大而增大。在相同冲击压力条件下，渗透率随气体压力的增加呈指数递减。随着冲击压力的增大，煤样的耗散能密度和损伤变量均呈指数增长。冲击扰动对煤中孔隙和裂隙的扩展有显著影响。随着损伤变量的增大，煤样孔隙度和渗透率增量均呈线性增加趋势。随着试验工作面抽采时间的增加，微震事件能量和瓦斯绝对涌出量均呈增加趋势。说明冲击波作用使煤体瓦斯渗流通道扩张，增强渗透性效果显著。

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引用次数: 0

Thermo-hydro-mechanical behavior of viscoelastic layered saturated soft soils under non-axisymmetric loadings 非轴对称荷载作用下粘弹性层状饱和软土的热-水-力学行为

IF 3.7 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-10-23 DOI: 10.1016/j.gete.2025.100761

Zhi Yong Ai, Wei Yong Feng, Lei Xu

Thermo-hydro-mechanical (THM) coupling behavior of layered transversely isotropic (TI) viscoelastic soils under non-axisymmetric loadings is a critical yet understudied topic in geotechnical engineering, especially for energy infrastructure where thermal gradients and horizontal mechanical loads induce time-dependent deformation. To address this problem, this study investigates the long-term behavior of soft soils under coupled thermo-mechanical loading and establishes a theoretical framework for the non-axisymmetric response of layered saturated viscoelastic media. First, a temperature-dependent viscoelastic soil skeleton model is proposed based on the classical Merchant model. Then, using the elastic–viscoelastic correspondence principle and Laplace transform, the constitutive relationship of the saturated thermo-viscoelastic media is derived in the transformed domain. Subsequently, by introducing the assumption of constant ratios among creep parameters in different directions, a thermo-viscoelastic model for TI media is developed. The governing ordinary differential equations for the non-axisymmetric THM coupling problem are then obtained by combining the governing equations, and applying Fourier series expansion and Hankel transform. The solution is derived using the extended precise integration method. Finally, numerical validation and parametric studies are conducted through representative examples. This semi-analytical solution provides a tool for predicting long-term non-axisymmetric THM deformation of layered TI viscoelastic soils, and offers actionable insights for the design assessment of energy geotechnical structures.

非轴对称荷载作用下层状横向各向同性粘弹性土的热-水-力耦合行为是岩土工程中一个关键但尚未得到充分研究的课题，特别是对于热梯度和水平机械载荷引起时间相关变形的能源基础设施而言。为了解决这一问题，本研究研究了热-力耦合加载下软土的长期行为，并建立了层状饱和粘弹性介质非轴对称响应的理论框架。首先，在经典Merchant模型的基础上，建立了温度相关的粘弹性土骨架模型。然后，利用弹粘弹性对应原理和拉普拉斯变换，推导了饱和热粘弹性介质在变换域内的本构关系。随后，通过引入蠕变参数在不同方向上的恒比假设，建立了TI介质的热粘弹性模型。结合控制方程，应用傅立叶级数展开和汉克尔变换，得到了非轴对称THM耦合问题的控制常微分方程。采用扩展精确积分法推导了该问题的解。最后，通过典型算例进行数值验证和参数化研究。这种半解析解为预测层状TI粘弹性土的长期非轴对称THM变形提供了工具，并为能源岩土结构的设计评估提供了可行的见解。

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引用次数: 0

Comparative experimental study on thermo-mechanical responses of phase-change and normal energy piles 相变桩与普通能量桩热-力响应对比试验研究

IF 3.7 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-10-20 DOI: 10.1016/j.gete.2025.100758

Jiaxin Liu, Chaoran Wang, Kehao Chen, Yang Shen, Chanjuan Han

Phase change energy piles (PCEP) have garnered attention from researchers in light of their higher equivalent specific heat and enhanced heat exchange potential compared to normal energy piles (NEP), making them effective for optimizing energy pile efficiency. However, research on the thermo-mechanical response of PCEP across different operational modes, environmental conditions, and multi-physical fields, particularly experimental studies, remains limited. Apart from this, few studies have clarified whether phase change occurs during both winter mode and summer mode. The determination of the phase state significantly affects the thermal efficiency. This study investigates the thermal and mechanical performance of PCEP and NEP through laboratory testing, comprehensively examining the effects of microencapsulated phase change material (microPCM) incorporation and variation in operational parameters. To address the low reliability of conventional PCMs, the microPCM with a unique shell structure was employed in the fabrication of PCEP. Key findings reveal that PCEP enhances heat energy harvesting under both winter and summer modes and promotes temperature recovery during cooling. Both pile types exhibit similar trends in normalized soil temperature change and pile heat reaction force. Moreover, PCEP experiences a slight increase in pile top force reduction during cooling, due to the higher thermal expansion coefficient of phase change concrete. The study confirms that PCEP offers a promising approach for optimizing energy efficiency and enhancing thermal management in geotechnical applications.

相对于普通能源桩（NEP），相变能源桩（PCEP）具有更高的等效比热和更强的热交换势，是优化能源桩效率的有效手段，因此受到了研究人员的关注。然而，关于PCEP在不同工作模式、环境条件和多物理场中的热-力学响应的研究，特别是实验研究仍然有限。除此之外，很少有研究澄清相变是否同时发生在冬季模态和夏季模态。相态的确定对热效率有重要影响。本研究通过实验室测试研究了PCEP和NEP的热力学性能，全面考察了微封装相变材料（microPCM）掺入和操作参数变化对PCEP和NEP的影响。为解决传统pcm可靠性低的问题，采用具有独特壳体结构的微pcm制造PCEP。主要研究结果表明，在冬季和夏季模式下，PCEP都能增强热能收集，并促进冷却过程中的温度恢复。两种桩型的归一化土温变化和桩热反力变化趋势相似。此外，由于相变混凝土的热膨胀系数较高，PCEP在冷却过程中桩顶减力略有增加。该研究证实，PCEP为优化能源效率和加强岩土工程应用中的热管理提供了一种很有前途的方法。

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引用次数: 0

Influence of matric suction on the behavior of energy pile groups under geometrically asymmetrical thermal cycling 几何不对称热循环条件下基质吸力对能量桩群性能的影响

IF 3.7 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-10-16 DOI: 10.1016/j.gete.2025.100760

Sina Afzalsoltani , Fardin Jafarzadeh , Salar Lakimahalleh

The behavior of energy pile groups under geometrically asymmetrical thermal loading in unsaturated soils presents a critical design challenge. The combined effects of group interaction, loading asymmetry, and soil suction on system performance are not fully understood. This study investigates these phenomena through 1 g physical model tests on 2 × 2 pile groups and isolated piles, with the results synthesized into a novel framework using contour maps to visualize the coupled system responses. Under mechanical load, group interaction effects were significant; an individual pile in the unsaturated group settled 26 % more than an isolated pile. Matric suction proved beneficial, reducing this settlement from 2.8 % of the pile diameter in the dry group to 2.1 % in the unsaturated group. During thermal cycling, asymmetrical loading induced significant cap tilting, peaking at 0.47 % and substantially exceeding the 0.2 % Eurocode serviceability limit. Load transfer mechanisms were also distinct between isolated and grouped piles. In unsaturated group tests, the mobilized end bearing of an energy pile increased by a factor of up to 2.5, which was substantially more than the 1.6-fold increase seen in isolated pile tests. Consequently, the soil pressure beneath the group pile tips was significantly greater, with the pressure under the energy pile in the G1P group being 1.87 times that recorded for the single pile. The study quantitatively demonstrates that while matric suction improves resistance, group interactions reduce per-pile efficiency, and asymmetrical thermal loading is the dominant factor controlling cap rotation, posing a significant serviceability risk.

非饱和土中几何不对称热荷载作用下能量桩群的性能是一个重要的设计挑战。群体相互作用、荷载不对称和土壤吸力对系统性能的综合影响尚未完全了解。本研究通过对2个 × 2个桩群和孤立桩进行1 g物理模型试验来研究这些现象，并利用等高线图将结果综合成一个新的框架来可视化耦合系统的响应。在机械载荷作用下，群体相互作用效应显著；非饱和群中单个桩的沉降比孤立桩多26% %。事实证明，基质吸力是有益的，将沉降从干桩组的2.8 %降低到非饱和桩组的2.1 %。在热循环过程中，不对称载荷引起显著的帽倾斜，峰值为0.47 %，大大超过0.2 %欧洲规范的使用极限。孤立桩和群桩之间的荷载传递机制也不同。在非饱和群试验中，能量桩的动端承载力增加了2.5倍，大大超过了隔离桩试验的1.6倍。因此，群桩桩尖下土压力明显较大，其中G1P组能量桩下土压力是单桩的1.87倍。该研究定量地表明，虽然基质吸力提高了阻力，但群相互作用降低了单桩效率，不对称热载荷是控制承台旋转的主要因素，带来了显著的使用风险。

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引用次数: 0

Impact of surface roughness on the mechanical behaviour of rock discontinuities 表面粗糙度对岩石不连续面力学行为的影响

IF 3.7 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-10-13 DOI: 10.1016/j.gete.2025.100757

Camilo Casagrande , Teresa Maria Pique , Diego Manzanal , Martín Sánchez

Geological storage of carbon dioxide (

C O_{2}

) is a key method for modern decarbonization, yet predicting the gas migration through the reservoir remains a geomechanical challenge. A major uncertainty stems from the potential reactivation of pre-existing rock discontinuities, whose shear strength is strongly influenced by surface roughness. In this work, we quantify the influence of roughness on discontinuity shear behaviour through triaxial direct shear tests. Three representative discontinuity geometries were prepared, their surface morphologies quantified with standard roughness parameters, and then loaded under normal stresses ranging from 0.7 MPa to 7 MPa. We compare three shear criteria and three ways to measure roughness to contrast the experimental results, assessing their suitability for predicting the shear strength of rock discontinuities. We found good agreement between roughness parameters and experimental shear strength for surfaces with greater waviness, whereas asperity-dominated discontinuities are systematically underpredicted. Additionally, greater normal displacement was observed where steep asperities were present, which is consistent with enhanced interlocking. Results are consistent across materials, indicating that surface morphology outweighs bulk strength. This analysis aims to improve the accuracy of shear strength predictions, which is essential for understanding subsurface behaviour in geological

C O_{2}

storage.

二氧化碳的地质储存是现代脱碳的关键方法，但预测天然气在储层中的运移仍然是一个地质力学挑战。一个主要的不确定性来自于先前存在的岩石不连续面的潜在重新激活，其抗剪强度受到表面粗糙度的强烈影响。在这项工作中，我们通过三轴直剪试验量化粗糙度对不连续剪切行为的影响。制备了三种具有代表性的不连续几何形状，用标准粗糙度参数量化其表面形貌，然后在0.7 MPa至7 MPa的法向应力范围内加载。我们比较了三种剪切准则和三种测量粗糙度的方法，以对比实验结果，评估它们在预测岩石不连续面抗剪强度方面的适用性。我们发现粗糙度参数和实验抗剪强度之间有很好的一致性，而粗糙度主导的不连续面被系统地低估了。此外，在陡坡处观察到更大的正常位移，这与增强的联锁相一致。结果是一致的材料，表明表面形态超过体积强度。该分析旨在提高抗剪强度预测的准确性，这对于了解地质CO2储存的地下行为至关重要。

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引用次数: 0

A new mechanism on how LCMs deposited stably to bridge during wellbore strengthening and its analytical model 井眼加固过程中lcm稳定沉积的新机制及其分析模型

IF 3.7 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-10-10 DOI: 10.1016/j.gete.2025.100756

Lisong Zhang , Kai Du , Wang Chen

LCMs (lost circulation materials) deposited stably to bridge (abbreviated as LCMs – DSTB) is the most critical step during the wellbore strengthening. However, it has not been fully understood on how LCMs deposited stably to bridge within the fracture. In view of this, a new mechanism was proposed to illustrate LCMs – DSTB, from two aspects of LCMs deposited compressively stably to bridge and LCMs deposited geometrically stably to bridge. Then, the analytical model was respectively established for LCMs – DSTB from two aspects, and three parameters were proposed to demonstrate LCMs – DSTB, namely, the coefficient of LCMs – DSTB, the location of LCMs – DSTB, and the time of LCMs – DSTB. Especially, to establish the analytical model, the fracture–related parameters were investigated such as the fracture width, the fracture length and the fracture pressure. The analytical model was validated by the numerical model, by comparisons of the coefficient of LCMs – DSTB, the location of LCMs – DSTB, and the time of LCMs – DSTB, as well as the fracture–related parameters, with the maximum deviation of less than 5.38 %. Finally, the effects of the loss rate, formation permeability, time difference, equivalent diameter on LCMs – DSTB were discussed. The results showed that: (1) the smaller loss rate, the shorter time difference and the larger formation permeability are beneficial for LCMs – DSTB; (2) the reasonable equivalent diameter of 0.4 was recommended for LCMs – DSTB.

lcm（漏失材料）稳定沉积到桥上（简称lcm - DSTB）是井筒加固过程中最关键的步骤。然而，对于lcm如何稳定沉积并在裂缝内桥接还没有完全了解。鉴于此，本文提出了一种新的lcm - DSTB机理，从lcm压缩稳定沉积到桥和lcm几何稳定沉积到桥两个方面来解释lcm - DSTB。然后，从两个方面分别建立了lcm - DSTB的解析模型，并提出了lcm - DSTB的系数、lcm - DSTB的位置和lcm - DSTB的时间三个参数来论证lcm - DSTB。为了建立分析模型，研究了裂缝宽度、裂缝长度和裂缝压力等与裂缝相关的参数。通过数值模型、lcm - DSTB系数、lcm - DSTB位置、lcm - DSTB时间以及裂缝相关参数的比较，验证了解析模型的正确性，最大偏差小于5.38 %。最后讨论了损失率、地层渗透率、时差、当量直径等因素对lcm - DSTB的影响。结果表明：(1)更小的损失率、更短的时差和更大的地层渗透率有利于lcm - DSTB；(2) LCMs - DSTB的合理等效直径为0.4。

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引用次数: 0

Research on rock failure characteristics under combined action of uniaxial stress and explosion 单轴应力与爆炸共同作用下岩石破坏特性研究

IF 3.7 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-10-08 DOI: 10.1016/j.gete.2025.100755

Zhibiao Guo , Jingwei Gao , Junao Zhu

Blasting technology is widely used in deep rock mass engineering, and the surrounding rock damage and crack propagation caused by blasting are usually affected by ground stress. The failure and propagation of cracks in boreholes surrounding rock under the combined action of uniaxial stress and blasting load are comprehensively studied. Explosion tests, mechanical analysis, and finite element modeling are used to verify these results from the perspectives of numerical simulation and field engineering. The LS-DYNA numerical software is used to verify the explosion experiment, and the corrected constitutive model is used to simulate the effects of different uniaxial stresses on rock loosening and shaped charge blasting failure characteristics. The fracture network is processed by ImageJ software, and the fracture morphology and fractal characteristics of rock surface are analyzed. Then, the change of fracture mode of uniaxial stress-induced shaped charge blasting is analyzed by means of elastic mechanics, and the mechanism of directional crack propagation is discussed. The results show that the crack initiation occurs along the zone of maximum tensile stress around the hole during loosening blasting. The application of uniaxial stress can restrain the speed and length of crack growth and control the direction of radial crack growth, which makes the crack propagation parallel to the stress direction more advantageous. In the process of shaped charge blasting, with the increase of uniaxial stress, the damage in the shaped charge direction gradually forms a complete failure plane, which significantly inhibits the crack growth in the non-shaped charge direction. This leads to fewer cracks, but faster spreads, and fewer fractal dimensions of cracks and rock damage. Finally, the test of cutting the top and relieving pressure of coalmine by shaped charge blasting has been carried out, and satisfactory results have been obtained. In deep rock mass engineering, it is suggested to use shaped charge blasting under anisotropic ground stress to achieve directional blasting so as to better maintain the integrity of surrounding rock and obtain a smoother blasting surface.

爆破技术在深部岩体工程中应用广泛，爆破引起的围岩破坏和裂纹扩展通常受到地应力的影响。全面研究了单轴应力和爆破荷载共同作用下钻孔围岩裂纹的破坏和扩展规律。从数值模拟和现场工程的角度，利用爆炸试验、力学分析和有限元建模来验证这些结果。利用LS-DYNA数值软件对爆炸实验进行验证，并利用修正后的本构模型模拟不同单轴应力对岩石松动及聚能爆破破坏特性的影响。利用ImageJ软件对裂缝网络进行处理，分析岩石表面裂缝形态和分形特征。然后，利用弹性力学分析了单轴应力诱导聚能爆破破裂模式的变化，探讨了定向裂纹扩展的机理。结果表明：在松动爆破过程中，裂纹沿孔周围最大拉应力区萌生；施加单轴应力可以抑制裂纹扩展的速度和长度，控制径向裂纹扩展的方向，使裂纹平行于应力方向扩展更为有利。在聚能爆破过程中，随着单轴应力的增大，聚能方向的损伤逐渐形成完整的破坏面，显著抑制了非聚能方向的裂纹扩展。这导致裂缝减少，但扩展速度加快，裂缝和岩石损伤的分形维数减少。最后进行了聚能爆破切顶卸压试验，取得了满意的效果。在深部岩体工程中，建议采用各向异性地应力作用下的聚能爆破实现定向爆破，以更好地保持围岩的完整性，获得更光滑的爆破面。

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引用次数: 0

Progressive failure of coal–rock under triaxial disturbance: From experimental and crack propagation modeling perspectives 煤岩在三轴扰动下的渐进破坏：从实验和裂纹扩展模型的角度

IF 3.7 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-10-04 DOI: 10.1016/j.gete.2025.100753

Yiqing Zhao , Wenjing Qin , Jinbo Liu , Aibing Jin , Shuaijun Chen

During deep mining, coal–rock masses are prone to dynamic stress redistribution and concentration under triaxial unloading disturbances, leading to progressive crack evolution and eventual instability. To investigate the underlying failure mechanism, triaxial unloading disturbance tests were carried out. Acoustic emission (AE) monitoring was used to track key indicators, including the RA/AF ratio, b-value, and dominant frequency. In addition, multifractal spectrum analysis was introduced to systematically characterize the crack evolution process of coal–rock under different unloading rates of confining pressure. The study divides the failure process into four stages and proposes an axial crack propagation model based on fracture mechanics to describe crack evolution under disturbed unloading conditions. The results indicate that, with increasing unloading rates, coal–rock failure is dominated by shear failure, accompanied by a reduction in the number of macroscopic cracks. The acoustic emission (AE) signals exhibit stronger multifractal characteristics and localized intensity heterogeneity, reflecting increased internal structural complexity and disorder. The developed crack propagation model provides theoretical support for the study of fracture evolution in geological materials under unconventional loading conditions and offers guidance for crack prediction and failure assessment in complex stress environments.

在深部开采过程中，煤岩体在三轴卸荷扰动下容易发生动应力重分布和集中，导致裂隙逐步演化，最终失稳。为了研究其潜在的破坏机制，进行了三轴卸荷扰动试验。采用声发射（AE）监测，对RA/AF比、b值、主导频率等关键指标进行跟踪。此外，引入多重分形谱分析，系统表征了煤岩在不同围压卸载速率下的裂纹演化过程。研究将破坏过程分为4个阶段，提出了基于断裂力学的轴向裂纹扩展模型来描述扰动卸载条件下的裂纹演化。结果表明：随着卸荷速率的增加，煤岩破坏以剪切破坏为主，宏观裂缝数量减少；声发射信号表现出更强的多重分形特征和局部强度非均质性，反映了内部结构复杂性和无序性的增加。所建立的裂缝扩展模型为非常规载荷条件下地质材料裂缝演化研究提供了理论支持，为复杂应力环境下裂缝预测和破坏评价提供了指导。

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引用次数: 0

Permeability evolution and predictive modeling in grout-reinforced fractured rock masses: An intelligent computational approach 注浆加固裂隙岩体渗透率演化与预测建模：一种智能计算方法

IF 3.7 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-10-02 DOI: 10.1016/j.gete.2025.100754

Yachao Guo , Junmeng Li , Yanli Huang , Yingshun Li , Jiachen Liu , Guiyuan Wang , Zuo Sun

The permeability evolution characteristics of grout-reinforced fractured rock masses significantly influence the seepage stability control in underground engineering. In this study, fractured sandstone specimens under various confining pressures (0–10 MPa) were prepared using a high-pressure triaxial testing system. Reinforcement was performed using coal gangue-fly ash-based grout, and the permeability variations under effective stresses (1–9 MPa) were systematically measured before and after grouting. A permeability prediction model for grouted rock masses was established by employing swarm intelligence algorithms (Particle Swarm Optimization (PSO), Genetic Algorithm (GA), and Grey Wolf Optimizer (GWO)), and an interactive computational platform was developed. The results show that post-grouting permeability decreased by 54.83–99.75 % compared to pre-grouting values, exhibiting a power-law decline with increasing effective stress. Using six key factors—including fracture stress state, initial permeability, and grouting parameters—an 80-sample training dataset was constructed. A backpropagation (BP) neural network (6-7-1 topology) optimized by the GWO achieved high-precision permeability prediction (R² = 0.997, MAE = 0.051). Finally, a Python-based intelligent interactive computing system was developed, integrating parameter control, model computation, and result visualization. This provides theoretical support and technical tools for engineering grout design.

注浆加固裂隙岩体的渗透演化特征对地下工程渗流稳定控制具有重要影响。本研究采用高压三轴试验系统制备了不同围压（0-10 MPa）条件下的裂隙砂岩试件。采用煤矸石-粉煤灰基注浆进行加固，系统测量了注浆前后有效应力（1 ~ 9 MPa）下的渗透率变化。采用粒子群算法（PSO）、遗传算法（GA）和灰狼优化算法（GWO）建立了注浆岩体渗透率预测模型，并开发了交互式计算平台。结果表明：灌浆后渗透率较灌浆前降低54.83 ~ 99.75 %，随有效应力的增加呈幂律递减；利用断裂应力状态、初始渗透率、注浆参数等6个关键因素，构建了80个样本的训练数据集。利用GWO优化的BP神经网络（6-7-1拓扑）实现了高精度的渗透率预测（R2 = 0.997, MAE = 0.051）。最后，开发了一个集参数控制、模型计算和结果可视化于一体的基于python的智能交互计算系统。这为工程注浆设计提供了理论支持和技术工具。

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引用次数: 0

A machine learning-based thermal-mechanical parameter inversion of energy pile considering thermo-mechanical behaviors 考虑热力学行为的基于机器学习的能量桩热力学参数反演

IF 3.7 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2025-09-28 DOI: 10.1016/j.gete.2025.100752

Chaoran Wang, Jiaxin Liu, Gia Trung Luu, Chanjuan Han

The thermal-mechanical properties of rock-soil are indispensable for the geotechnical investigation of energy piles according to design codes. The thermal parameters of the stratum and pile are commonly determined through thermal response tests (TRT), and the mechanical parameters are obtained via sampling or in-situ testing, with some parameters also assigned based on engineering experience. However, on the one hand, TRT and in-situ testing are costly and labor-intensive processes that last nearly one week. On the other hand, the accuracy of personal experience on parameter determination is not guaranteed. Parameter inversion adjusts numerically modelled values (originally from tests/experience) to compensate for sampling effects, stratigraphic variations, and human biases that create simulation errors. The machine learning-based surrogate model, experiencing a surge in popularity in recent years, is a promising solution for inversion acceleration. By training on precomputed numerical simulation results, the surrogate model emulates the system’s behavior at significantly faster speeds, simultaneously reducing computational time and financial costs compared to traditional numerical modelling. This study proposes a novel method for parameter inversion with machine-learning-based surrogate models. A numerical model is first established by replicating a reduced-scale physical test capturing the thermal-mechanical behaviors of the energy pile. The Latin hypercube sampling is subsequently utilized to generate sufficient data for XGBoost model development, where the sensitivity analysis is subsequently carried out for parameter screening. The parameter inversion is then implemented with non-dominated sorting genetic algorithms. The effectiveness of the method is validated using 4 real-case test conditions. The results demonstrate that the surrogate model attains high accuracy with an R² of temperature and axial forces above 0.97 and 0.9, respectively. Lastly, the results of parameter inversion indicate a promising and optimistic prospect for the proposed inversion method, which can reveal the comprehensive parameters of the material to a certain extent. This study presents an efficient method for parameter inversion of energy piles while providing a perspective of fast determination of rock-soil thermal properties.

根据设计规范进行能源桩岩土工程勘察时，岩土热力学特性是必不可少的。地层和桩的热参数一般通过热响应试验（TRT）确定，力学参数一般通过抽样或现场测试获得，部分参数也根据工程经验确定。然而，一方面，TRT和原位测试是一个耗时近一周的昂贵和劳动密集型过程。另一方面，不能保证个人经验对参数确定的准确性。参数反演调整数值模拟值（最初来自测试/经验），以补偿采样效应、地层变化和造成模拟误差的人为偏差。基于机器学习的代理模型近年来越来越受欢迎，是一种很有前途的反演加速解决方案。通过对预先计算的数值模拟结果进行训练，代理模型可以以更快的速度模拟系统的行为，同时与传统的数值模拟相比，减少了计算时间和财务成本。本研究提出了一种基于机器学习的代理模型参数反演的新方法。首先通过模拟能量桩的小尺度物理试验，建立了能量桩的数值模型。随后利用拉丁超立方体采样为XGBoost模型开发生成足够的数据，随后进行敏感性分析以进行参数筛选。然后用非支配排序遗传算法实现参数反演。通过4个实际测试条件验证了该方法的有效性。结果表明，该模型具有较高的拟合精度，温度和轴向力的R2分别在0.97和0.9以上。最后，参数反演结果表明，所提出的反演方法具有良好的应用前景，能在一定程度上揭示材料的综合参数。该研究为能量桩参数反演提供了一种有效的方法，同时为快速确定岩土热特性提供了前景。

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