摘要
用"钻孔法"消除穿刺风险,在工程应用中已经取得了成功,但其相关研究和评估方法却十分有限。基于ABAQUS软件提供的耦合欧拉-拉格朗日方法,对"钻孔法"消除穿刺风险进行了有限元模拟,详细地分析了"钻孔法"消除穿刺风险的作用机制,给出了钻孔数量、钻孔深度、钻孔直径和范围对于穿刺风险消除效果的影响规律。分析结果表明,"钻孔法"消除穿刺风险的效果与钻孔数量(面积)、钻孔直径和钻孔深度成正比,但与桩靴面积外钻孔范围成反比;钻孔直径对于峰值承载力的影响比其他因素小,桩靴面积外钻孔范围对峰值承载力几乎无影响,但对后峰值承载力影响较大。基于75组数值模拟结果,提出了一种评估"钻孔法"消除穿刺风险效果的评估方法,同时考虑了桩靴覆盖面积内外的钻孔作用,对于工程实践具有很强的指导意义。
Punch-through is one of the main threats to the safe operation of jack-up units. Perforation method has been successfully implemented in engineering practice to mitigate punch-through potentials. However its research and evaluation method are still limited. With the coupled Eulerian-Lagrangian method provided by ABAQUS, finite element analysis of punch-through mitigation with perforation is carried out. The spudcan is modeled as Lagrangian domain, while the soil is modeled as Eulerian domain, among which the holes created by perforation drilling is initially modeled as void. The mechanism by which perforation mitigates punch-through potential is analyzed, which shows that the perforation drilling turns general failure mechanism into local failure mechanism in stiff-over-soft clay layers. And the effects of hole number, hole depth, hole diameter and extent are studied. It is shown that the soil plug during penetration into stiff-over-soft clay decreases with hole number, hole depth and hole diameter. Correspondingly, the efficiency of punch-through mitigation with perforation is proportional to hole number, hole depth and hole diameter. However, the effect of hole diameter on the peak resistance is relatively very small. The extent of drilling holes outside the spudcan perimeter has little effect on the peak resistance, while it has a larger effect on the post-peak resistance. An evaluation method for the efficiency of peak resistance reduction with perforation method is proposed by fitting from 75 cases of numerical simulation. It takes into account the perforation drilling area both outside and inside the spudcan perimeter; hole diameter and hole depth, which is of great significance for engineering practice.
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2016年第S1期563-569 576,576,共8页
Rock and Soil Mechanics
基金
国家自然科学基金(No.51379214)
山东省自然科学基金青年基金(No.ZR2015EQ006)~~
关键词
钻孔法
穿刺风险
承载力曲线
耦合欧拉-拉格朗日法
perforation
punch-through potential
load-penetration profile
coupled Eulerian-Lagrangian method
