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《建筑科学与工程学报》[ISSN:1673-2049/CN:61-1442/TU]

卷:

42卷

期数:

2025年04期

页码:

177-186

栏目:

岩土工程

出版日期:

2025-07-10

文章信息/Info

Title:

Calculation of safety thickness of underlying filling karst cave roof of bridge pile foundation

文章编号:

1673-2049(2025)04-0177-10

作者:

王成成,张莎莎,杨晓华,李吉富

(长安大学 公路学院,陕西 西安 710064)

Author(s):

WANG Chengcheng, ZHANG Shasha, YANG Xiaohua, LI Jifu

(School of Highway, Chang'an University, Xi'an 710064, Shaanxi, China)

关键词:

下伏溶洞;  安全厚度;  桥梁桩基;  正交试验;  多元回归分析

Keywords:

underlying karst cave;  safety thickness;  bridge pile foundation;  orthogonal test;  multiple regression analysis

分类号:

TU921

DOI:

10.19815/j.jace.2023.05063

文献标志码:

A

摘要:

当山区桥梁桩基存在下伏溶洞时,桩基应当与溶洞保持一定的安全厚度,以保证桩基和桥梁的稳定性。结合理论分析与数值试验对桩基下伏溶洞顶板安全厚度进行计算,将溶洞顶板分别简化为固支梁、简支梁和悬臂梁,基于结构力学理论推导出不同模型的充填溶洞顶板安全厚度计算公式; 采用FLAC3D软件与正交试验设计方法,分析了围岩水平、溶洞跨度、高跨比、桩径、嵌岩深度对顶板安全厚度的影响规律及其显著性,建立了桥梁桩基下伏溶洞顶板最小安全厚度预测模型。结果表明:桩基下伏溶洞顶板安全厚度与围岩水平、溶洞跨度成正比,与高跨比成反比,随着嵌岩深度的增大呈现先增加后减小的趋势,随桩径的变化影响并不明显; 整体影响程度从大到小依次为溶洞跨度、嵌岩深度、围岩水平、桩径、高跨比,各因子权重分别为0.679、0.140、0.044、0.018、0.011; 工程实例检验结果表明,采用理论分析预测安全厚度与数值分析结果基本吻合,基于力学模型预测的安全厚度较为保守,两个工程实例的数值模拟预测安全厚度相比力学模型预测结果分别降低1.47 m与0.59 m,且数值分析方法在应用于不同地质情况时切实可行,具有一定的准确性和代表性。

Abstract:

When the pile foundation of bridges in mountainous areas has underlying karst cave, the pile foundation should maintain a certain safe thickness with the karst cave to ensure the stability of the pile foundation and bridge. Combined with theoretical analysis and numerical test, the safety thickness of underlying karst cave roof of pile foundation was calculated, and the karst cave roof was simplified into solid supported beam, simple supported beam and cantilever beam respectively. By using FLAC3D software and orthogonal experimental design method, the influence rules and significance of surrounding rock level, karst cave span, height-to-span ratio, pile diameter and rock-socking depth on roof safety thickness were analyzed, and the prediction model of minimum safe roof thickness of underlying karst cave of bridge pile foundation was established. The results show that the safety thickness of underlying karst cave roof of pile foundation is directly proportional to the level of surrounding rock and karst cave span, and inversely proportional to the height-to-span ratio. With the increase of rock-socking depth, the safety thickness of karst cave roof increases first and then decreases, and the influence of pile diameter is not obvious. The overall influence degree from large to small is karst cave span, rock-socking depth, surrounding rock level, pile diameter, height-to-span ratio, and the weight of each factor are 0.679, 0.140, 0.044, 0.018, 0.011, respectively. The test results of engineering cases show that the safety thickness predicted by theoretical analysis is basically consistent with the results of numerical analysis, and the prediction of safety thickness based on mechanical model is conservative, and compared with the mechanical model prediction result, the prediction of safety thickness of two engineering examples by numerical simulation test is reduced by 1.47 m and 0.59 m, respectively. Moreover, the numerical analysis method is feasible when applied to different geological conditions and has certain accuracy and representativeness.

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相似文献/References:

备注/Memo

备注/Memo:

收稿日期:2023-05-06
基金项目:陕西省自然科学基础研究计划项目(2019JM-147); 民航机场规划设计研究总院有限公司科研项目(220221220342)
通信作者:张莎莎(1982-),女,工学博士,副教授,E-mail:zss_lx@126.com。
Author resume: ZHANG Shasha(1982-), female, PhD, associate professor, E-mail: zss_lx@126.com.

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更新日期/Last Update: 2025-07-10