粘性土中抗滑桩离心模型试验研究
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摘要
滑坡是斜坡破坏型式中分布最广、危害最严重的一种地质灾害,我国是世界上受滑坡灾害损失最为严重的国家之一。三峡工程、青藏铁路、西气东输、西电东送和汶川地震灾后重建等一大批关系国计民生的重大工程相继启动。因此,迫切需要对滑坡治理方法进行系统研究并以此为工程实践提供科学的依据。
抗滑桩作为整治滑坡的主要手段之一,在滑坡治理工程中取得了极为广泛的应用。但由于目前抗滑桩的理论研究与工程实践存在较大的差距,尤其突出表现在抗滑桩工程中抗滑桩设计参数确定具有很大的随意性,缺乏合理的标准和科学的理论依据,因此其设计方案很难达到安全和经济的双重目的。造成这种现象的原因主要是对抗滑桩桩间土拱效应的作用机理尚未完全弄清楚。
本文主要研究内容及所取得的研究成果包括如下几个方面:
①以离心模型试验为基础,结合当前滑坡治理工程中的抗滑桩设计原则和内力计算方法,研究抗滑桩桩身摩阻力、弯矩、剪力分布以及随着桩间距的增大对抗滑桩内力的影响。
②通过三维数值模型,分析桩和周围岩土体的变形与应力变化趋势,深入研究了抗滑桩与滑坡相互作用的机理,提出了基于土拱效应的粘土中抗滑桩合理桩间距的计算公式,确定了粘土中合理的桩间距为桩径的4倍左右。
③通过分析得出在其它变量一定的情况下,临界桩间距随着粘聚力、内摩擦角的增大而增大。当土体内摩擦角?一定时,土拱高度的变化与桩间距有关,大约是桩间净距的1/3。
Of all slope failure types,landslide is the widest distribution and the most severe geological hazard.Our nation is one of the countries suffering the mostserious landslide hazard loss in the world. The Three Gorges Reservoir project,Qinghai-Tibet railway project,West-East natural gas transferring project, West-East electricity transmission project,Wenchuan earthquake reconstruction,etc,agreat number of key project related to national welfare and the people’s livelihood aresuccessively carried out.As a result,it is urgent to systematic study the way of controlling the landslides to provide scientific basis for engineering practice.
Anti-slide pile is one of the most significant measures for controlling the landslide,and it is widely used in the landslide control project.However,due to thegap between the theory study and the engineering practice of anti-slide pile,the determination of design parameters of anti-slide pile always depend on engineering experience,lacking of reasonable standard and scientific theory basis. As a result,the design scheme is difficult to achieve both safety and economy. The main reason for this phenomenon is the interaction mechanism of soil-arch effect between anti-silde piles has not yet fully clear.
The main research work done in this thesis consists of the following parts:
①Base on the centrifugal model test,combined with the current design principles and internal force calculation method of anti-slide pile to study the friction resistance、the bending moment、shear force distrbution of anti-slide pile and the impact of internal forces to anti-slide pile with the pile spacing changing.
②Through the three-dimensional numerical model to analyze the pile and thesurrounding rock and soil deformation and stress changes in trends, on the base of studying on the interaction mechanism of anti-slide piles and landslide it can propose the calculation method of critical space between anti-slide pile in clay soil.The reasonable distance of anti-slide pile is about 4 times of the pile diameter in clay soil.
③In the other variables obtained by analyzing certain circumstances, the critical spacing between piles increases with cohesion、internal friction angle increaseing. When the soil friction angle is a certain body, changes of the soil arch height is related to spacing between piles and about 1/3 of spacing betweenpiles.
抗滑桩作为整治滑坡的主要手段之一,在滑坡治理工程中取得了极为广泛的应用。但由于目前抗滑桩的理论研究与工程实践存在较大的差距,尤其突出表现在抗滑桩工程中抗滑桩设计参数确定具有很大的随意性,缺乏合理的标准和科学的理论依据,因此其设计方案很难达到安全和经济的双重目的。造成这种现象的原因主要是对抗滑桩桩间土拱效应的作用机理尚未完全弄清楚。
本文主要研究内容及所取得的研究成果包括如下几个方面:
①以离心模型试验为基础,结合当前滑坡治理工程中的抗滑桩设计原则和内力计算方法,研究抗滑桩桩身摩阻力、弯矩、剪力分布以及随着桩间距的增大对抗滑桩内力的影响。
②通过三维数值模型,分析桩和周围岩土体的变形与应力变化趋势,深入研究了抗滑桩与滑坡相互作用的机理,提出了基于土拱效应的粘土中抗滑桩合理桩间距的计算公式,确定了粘土中合理的桩间距为桩径的4倍左右。
③通过分析得出在其它变量一定的情况下,临界桩间距随着粘聚力、内摩擦角的增大而增大。当土体内摩擦角?一定时,土拱高度的变化与桩间距有关,大约是桩间净距的1/3。
Of all slope failure types,landslide is the widest distribution and the most severe geological hazard.Our nation is one of the countries suffering the mostserious landslide hazard loss in the world. The Three Gorges Reservoir project,Qinghai-Tibet railway project,West-East natural gas transferring project, West-East electricity transmission project,Wenchuan earthquake reconstruction,etc,agreat number of key project related to national welfare and the people’s livelihood aresuccessively carried out.As a result,it is urgent to systematic study the way of controlling the landslides to provide scientific basis for engineering practice.
Anti-slide pile is one of the most significant measures for controlling the landslide,and it is widely used in the landslide control project.However,due to thegap between the theory study and the engineering practice of anti-slide pile,the determination of design parameters of anti-slide pile always depend on engineering experience,lacking of reasonable standard and scientific theory basis. As a result,the design scheme is difficult to achieve both safety and economy. The main reason for this phenomenon is the interaction mechanism of soil-arch effect between anti-silde piles has not yet fully clear.
The main research work done in this thesis consists of the following parts:
①Base on the centrifugal model test,combined with the current design principles and internal force calculation method of anti-slide pile to study the friction resistance、the bending moment、shear force distrbution of anti-slide pile and the impact of internal forces to anti-slide pile with the pile spacing changing.
②Through the three-dimensional numerical model to analyze the pile and thesurrounding rock and soil deformation and stress changes in trends, on the base of studying on the interaction mechanism of anti-slide piles and landslide it can propose the calculation method of critical space between anti-slide pile in clay soil.The reasonable distance of anti-slide pile is about 4 times of the pile diameter in clay soil.
③In the other variables obtained by analyzing certain circumstances, the critical spacing between piles increases with cohesion、internal friction angle increaseing. When the soil friction angle is a certain body, changes of the soil arch height is related to spacing between piles and about 1/3 of spacing betweenpiles.
引文
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[9]戴自航,彭振斌.地基系数法在岩体抗滑桩内力计算中的应用[J].湖南大学学报.2002(4).30-31
[10]JGJ94-94.建筑桩基技术规范[S]
[11]徐良德,尹道成,刘惠明.滑体为松散介质时桩前滑体抗力分布[C].滑坡文集(第六集).北京.中国铁道出版社.1988
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