Numerical Study of Storm Surge Inundation in the Southwestern Hangzhou Bay Region During Typhoon Chan-Hom in 2015

Storm surge inundation is a major concern in marine hazard risk assessment during extreme weather conditions.In this study,a high-resolution coupled model(the ADVanced CIRCulation model+the Simulating WAves Nearshore model)was used to investigate the storm surge inundation in the southwestern Hangzhou Bay region during Typhoon Chan-hom in 2015.The simulated hydrodynamic processes(sea surface wave and storm tide)were validated with measured data from wave buoys and tide gauges,indicating that the overall performance of the model was satisfactory.The storm surge inundation in the coastal area was simulated for several idealized control experiments,including different wave effects(wave-enhanced wind stress,wave-enhanced bottom stress,and wave radiation stress).Dike overflowing cases with different dike heights and dike breaking cases with different dike breach lengths were considered in the simulation.The results highlight the necessity of incorporating wave effects in the accurate simulation of storm surge inundation.Dike height significantly influences the magnitude and phase of the maximum inundation area in the dike overflowing cases,and dike breach length is an important factor impacting the magnitude of the maximum inundation area in the dike breaking cases.This study may serve as a useful reference for accurate coastal inundation simulation and risk assessment.     

大同--运城高速公路某软基复合地基检测结果分析

以山西大运高速公路某段软基处理为例,从挤密碎石桩的加固机理和破坏方式入手,通过对软基复合地基的原位测试结果分析,得出碎石桩不但提高了地基的承载力,增加了桩间土的强度,减少了地基沉降,而且消除或减轻了地基的液化,使复合地基承载力达到了设计要求,特别是为以后在高速公路修筑中的软基处理提供了参考资料.     

秦巴山区软岩地基桥桩承载性状试验研究

为了研究软岩地基桥桩的荷载传递性状、破坏机理,并获取在该地质条件下更为可靠的桩基计算参数,对秦巴山区软岩地基3根钻孔灌注试桩进行竖向静载试验.结果表明:秦巴山区软岩地基桥桩试桩荷载沉降曲线呈陡降型,实测竖向极限承载力为20500kN,桩的破坏方式为桩身材料强度破坏;淤泥质亚黏土地层中的碎石起到一定的骨架作用,增强了此地层桩极限侧阻力,发挥极限侧阻力所需的桩土(岩)相对位移为4~8mm;强风化砾岩表现为加工软化型,发挥极限侧阻力所需的桩土(岩)相对位移为3~8mm;中风化砂砾岩表现为明显的加工硬化型,所需的桩岩相对位移大,且桩极限侧阻力的特征点不明显;淤泥质亚黏土地层桩侧阻力占总荷载的60%~70%,随着桩顶荷载的逐步加大,该地层桩侧阻力所占比例不断下降,而嵌岩段桩侧阻力所占比例逐渐上升,达到55%~65%,嵌岩段桩侧阻力沿桩深的分布曲线表现出非线性的特征;试桩为端承摩擦桩,桩端阻力约占桩顶荷载的20%左右,且未充分发挥,在上部结构允许的沉降范围内,适当增加桩端的沉降有利于端阻力的发挥;桩侧阻力先于端阻力发挥,建议单桩承载力设计时分别采用不同的端阻力和侧阻力安全系数.     

用素土桩挤密法处理陇东湿陷性黄土地基

素土桩挤密地基由桩间挤密土和回填素土夯实的桩体组成，它是一种人工“复合地基”。其作用是通过素土桩挤密法提高地基土的密实度，从而对湿陷性黄土达到消除浅部或深部的部分或全部湿陷性的作用，并改善地基承载能力，减少地基变形。本文通过现场单桩、群桩单元体轻便触探、小环刀深层取样、开剖取样等方法对场地地基土挤密前、后干重度和压实系数进行了对比分析，判定用素土桩挤密法处理陇东湿陷性黄土地基的可行性。     

强夯法加固河堤地基的效果分析—以日东高速济宁西连接线为例

以日东高速济宁西连接线K11段强夯为例,对强夯前后的河堤地基进行了对比勘察研究。结果表明,强夯后,地基土的密实度,重度及干重度增加,孔隙比、粘聚力、内磨擦角、压缩模量明显比强夯前减小,同一深度土层标贯击数有所增加,土的锥尖阻力和侧摩阻力也有不同程度的提高,对比不同深度孔隙比变化的幅度和强夯前后锥尖阻力和侧摩阻力变化曲线,得出了强夯的有效加固深度。     

Study on preventing frost heave methods for highway foundation in seasonal frozen area

In order to resolve the frost-heave problem of highway foundation, firstly, the author discussed the law to frost heave of highway roadbed and gave an analysis on its influencing factors, such as soil, water and temperature. Meanwhile, sand clay and silt are given a classification according to frost heave ratio. Secondly, the roadbed frozen damage shows to frost heave and froze boiling based on the frost heave law and its influencing factors. In addition, taking some highway as an example and some principle suggestion was given through the theory on providing frostbite methods for highway foundation frost heave in seasonal frozen area. Specially, an effective method, STYROFOAM extruded polystyrene foam was introduced.     

山区公路软基病害研究

随着高等级公路建设规模的扩大，山区公路所面临的路基病害特别是软土路基病害问题也逐渐增多。结合对陕南勉(县)一宁(强)高速公路工程实例分析，对山区软土成因及其特性进行了初步分析，认为山区软土属以坡洪积、湖积和冲积为主的软土，也有少量是由坡残积物堆积而形成。山区软土的特殊性表现在成分的复杂性、分布的不均匀性、隐蔽性和物理力学性质的特殊性。根据其特性以及中国山区公路软基普遍存在的病害问题，总结了山区公路软基的主要病害类型为剪切拉裂破坏、浸水沉陷破坏、剥蚀坍塌破坏、推挤滑动破坏。还提出了相应的软基处理方法及建议。     

Study on preventing frost heave methods for highway foundation in seasonal frozen area

In order to resolve the frost-heave problem of highway foundation,firstly,the author discussed the law to frost heave of highway roadbed and gave an analysis on its influencing factors,such as soil,water and temperature.Meanwhile,sand clay and silt are given a classification according to frost heave ratio.Secondly,the roadbed frozen damage shows to frost heave and froze boiling based on the frost heave law and its influencing factors.In addition,taking some highway as an example and some principle suggestion was given through the theory on providing frostbite methods for highway foundation frost heave in seasonal frozen area.Specially,an effective method,STYROFOAM extruded polystyrene foam was introduced.     

水泥粉体深层喷射搅拌桩复合地基处理及其效果

水泥粉体深层喷射搅拌桩与干振碎石桩〔１〕、干振灰土桩等一样,也是处理松软地基土的一种有效方法。但与干振碎石桩等其他挤密型复合地基处理方法不同,水泥粉体深层喷射搅拌桩属于摩擦桩型。由于天然地基土对桩体的侧摩擦力和端阻力的共同作用,使复合地基的承载力大幅度提高。然而人们普遍认为,水泥粉体深层喷射搅拌桩法复合地基处理不能解决场地土的液化问题。本文通过工程实例和瑞雷波检测结果,证实了该方法处理的复合地基,除了承载力有较大幅度的提高外,地基土的抗液化能力也可以得到相应的加强。     

Measured Performance and Analysis of the Residual Settlement of a PVD-Improved Marine Soft Ground

Prefabricated vertical drains(PVDs) are commonly used to shorten the drainage path for consolidation as part of the improvement of marine soft ground. Many studies that focus on the primary consolidation settlement of PVD-improved soft ground have been conducted; however, residual settlement has been scarcely investigated. Residual settlement is the net effect of secondary compression and the remaining primary consolidation and generally occurs while the facilities are operating. In this study, residual settlement was investigated using the measured field settlement data obtained from the surface settlement plate and multilayer settlement gauges. This study determined that PVD still has some effect on residual settlement and can reduce the settlement times. Residual settlement is only related to the PVD-improved soil layer and only occurs significantly in the middle zone of that layer over a few months. The middle zone may be related to the time delay of excess pore water pressure dissipation. This study concluded that the remaining primary consolidation in the PVD-improved soil layer is the primary cause of residual settlement, whereas secondary compression in the PVD-improved soil layer is only a minor cause.