引用本文: 仇安兵. 有限空间新建设施基坑开挖沉降特征及小变形控制[J]. 工程科学学报, 2024, 46(4): 735-743.
QIU Anbing. Study on settlement characteristics and microdeformation control of foundation pit excavation in new facilities with limited space[J]. Chinese Journal of Engineering, 2024, 46(4): 735-743.
 Citation: QIU Anbing. Study on settlement characteristics and microdeformation control of foundation pit excavation in new facilities with limited space[J]. Chinese Journal of Engineering, 2024, 46(4): 735-743.

## Study on settlement characteristics and microdeformation control of foundation pit excavation in new facilities with limited space

• 摘要: 针对有限空间新建基坑变形控制难题，采用理论分析、数值推演和工程实践相结合的研究方法，建立了考虑应力释放的有限空间夹持力学模型，推导了夹持应力与地层损伤因子的函数关系，研究了应力释压孔对有限空间地层应力的影响特征，提出了变形支挡–应力阻隔一体结构控制方法，并通过北京科技大学工程实践基地（二期）验证该方法的有效性. 结果表明，地层损伤因子与夹持应力呈线性负相关关系，随开挖深度逐渐增大，布设释压孔可有效降低有限空间夹持应力，释压孔有利于调整地层夹持应力和控制地层变形，变形控制率为33.48%～58.72%，且变形支挡–应力阻隔一体结构控制方法的水平变形控制率为28.57%～37.91%，地层沉降变形控制率为36.86%～54.26%，与数值模型计算结果趋势相同，论证了理论分析和数值推演结果有效性，为有限空间基坑稳定性控制提供数据支撑.

Abstract: To address the problem of deformation control of a new foundation pit in finite space, a mechanical model of strong mutual clamping in finite space considering stress release is developed based on the plane strain method of elastic mechanics by combining theoretical analysis, numerical deduction, and engineering practice. The formation damage factor is introduced to distinguish the structural failure state of the formation, and the functional relationship between the clamping stress and the formation damage factor is obtained. A numerical deduction model of the stress barrier in finite space is constructed. The influence of stress release holes on the stress structure of finite space is examined, and an integrated structural control method for deformation support and stress barrier is proposed. The effectiveness of the method was validated by the engineering practice base project of the University of Science and Technology Beijing. The findings reveal that under the strong mutual clamping effect between the lateral earth pressure of the existing building and the supporting reaction force of the foundation pit, the formation damage factor has a linear negative correlation with clamping stress. The vertical stress in the shallow part of the model without a pressure relief hole increases gradually and then decreases and sets near 21.2–22.5 kPa. The vertical stress level of the model with a pressure relief hole is ～40 kPa lower than that of the model without a pressure relief hole. The horizontal stress of the shallow layer without the pressure relief hole first increases, then decreases, and gradually increases to a maximum value of 94.72 kPa in the early stage of foundation pit excavation. The peak value of horizontal stress is lowered by 65.51%, and the effective release of formation stress is 43.55%–65.51%. The settlement of the foundation pit increases gradually with increasing excavation time. The maximum horizontal deformation of the model with a pressure relief hole is 15.86 mm lower than that of the model without a pressure relief hole, and the vertical deformation is reduced by 39.53%. The effective control rate of formation deformation is 33.48%–58.72%. The horizontal deformation control rate of the deformation support–stress barrier integrated structure support method is 28.57%–37.91%, and the ground settlement deformation control rate is 36.86%–54.26%, which confirms the effectiveness of the method. This work offers data support for the stability control of foundation pits in limited space.

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