| 基于区间非概率可靠性方法的岩溶区桩基下溶洞顶板稳定性评价 |
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| 引用本文： | 秦溯,李云安,孙琳.基于区间非概率可靠性方法的岩溶区桩基下溶洞顶板稳定性评价[J].水文地质工程地质,2019,0(5):81-88. |
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| 作者姓名： | 秦溯 李云安 孙琳 |
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| 作者单位： | 中国地质大学（武汉）工程学院，湖北 武汉430074 |
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| 基金项目： | 国家自然科学基金委与广东省联合基金重点基金项目资助“基于地学大数据的城市地质灾害智能监测、模拟、管控、预警”（U1711266） |
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| 摘 要： | 岩溶区桩基下溶洞顶板稳定性影响因素取值的不确定性及其样本数量的有限性,给桩基下溶洞顶板稳定性的评价带来了一定困难。根据现有研究成果,建立桩基下溶洞顶板抗冲切、抗剪切和抗弯力学简化模型,并从理论上推导相应的稳定性验算公式。在此基础上,结合区间分析理论和结构非概率可靠性度量方法,提出了基于区间非概率可靠性方法的桩基下溶洞顶板稳定性评价方法。该方法采用MATLAB中的INTLAB工具箱进行区间运算,并运用截断法消除运算过程中的区间扩展现象,最后通过比较溶洞顶板体系的非概率可靠性指标η与1的大小来判断桩基下溶洞顶板稳定性。以丹霞高速互通中D匝道2#桩基下溶洞为例,计算出该桩基下溶洞顶板体系的非概率可靠性指标η=7.95,该值大于1说明该桩基下溶洞顶板处于稳定状态,且评价结果与工程实际相符,表明了该方法的合理性与可行性。分别以3种功能函数为单位,研究当区间变量的变异系数C不同时(C从0.01递增至0.1),对应非概率可靠性指标η的变化规律。研究表明,随各区间变量变异系数C的增大,相应非概率可靠性指标呈不同程度的降低,其中溶洞顶板厚度h的变异性对评价结果影响最大,其次为桩端阻力分担比T,桩顶反力F的影响相对最小。
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| 关 键 词： | 岩溶区 桩基下溶洞顶板 稳定性评价 区间非概率可靠性方法 非概率可靠性指标 变异性 |
| 收稿时间： | 2019-03-21 |
| 修稿时间： | 2019-04-16 |
Stability evaluation of karst cave roof under pile in karst areas based on the interval non-probabilistic reliability method |
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| QIN Su,LI Yunan,SUN Lin.Stability evaluation of karst cave roof under pile in karst areas based on the interval non-probabilistic reliability method[J].Hydrogeology and Engineering Geology,2019,0(5):81-88. |
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| Authors: | QIN Su LI Yunan SUN Lin |
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| Institution: | Faculty of Engineering, China University of Geosciences, Wuhan, Hubei430074, China |
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| Abstract: | The uncertainty and finiteness of the factors affecting the stability of karst cave roof under pile in karst areas bring about some difficulties to the evaluation of the stability of karst cave roof under pile. According to the existing research results, the punching, shearing and bending mechanical simplified models of karst cave roof under pile tip are established, and the corresponding stability checking formulas are derived. Combined with the interval analysis theory and structural non-probabilistic reliability measurement method, the stability evaluation method of karst cave roof under pile tip based on interval non-probabilistic reliability method is proposed. This method uses the INTLAB toolbox in MATLAB to perform interval operations, and then uses the truncation method to eliminate the interval expansion phenomenon in the process. The stability of karst cave roof under pile is judged by comparing the relationship between the non-probabilistic reliability index η and 1. The karst cave under the D ramp 2# pile in the Danxia grade separation area is taken as an example, and the non-probabilistic reliability index η of the karst cave roof under 2# pile is calculated to be 7.95. η greater than 1 indicates that the karst cave roof under 2# pile is in a stable state. The evaluation result is consistent with the actual situation, indicating the rationality and feasibility of the method. The three performance functions are used as the unit to study the variation law of the non-probabilistic reliability index η when the coefficient of variation C of the interval variable is different (C increases from 0.01 to 0.1). The results show that with the increase of the coefficient of variation C of each interval variable, the corresponding non-probabilistic reliability indexes are reduced to varying degrees. The variability of the thickness of karst cave roof h has the greatest influence on the evaluation results, followed by the sharing ratio of pile tip resistance T, and the counterforce of pile tip F has the least influence. |
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| Keywords: | karst area karst cave roof under pile stability evaluation interval non-probabilistic reliability method non-probabilistic reliability index variability |
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