振冲碎石桩法在可液化砂土地基中的应用

采用振冲碎石桩法加固可液化砂土地基,对于提高地基承载力,消除液化,减少基础沉降量和不均匀沉降,有着重要作用。同时具有施工简便、快速、经济的优点。在曹妃甸输油泵站的基础加固中,采用振冲碎石桩法,收到良好的效果,达到了提高承载力、消除液化、减少沉降的作用。对振冲碎石桩加固软土基础的施工技术参数、施工方法、施工质量控制等作了阐述。     

振冲碎石桩复合地基的实践应用

通过工程实例,介绍了砂土地基采用振冲碎石桩进行处理的施工工艺、施工参数、施工过程的质量控制,以及对处理后的桩体、复合地基、砂土液化消除情况进行的工程质量检测。质量检测表明,桩体密实,质量较好,经振冲碎石桩处理后的复合地基承载力特征值不小于250 kPa,满足设计要求,处理范围内砂土的液化已全部消除。     

振冲法加固砂土地基的试验及应用

根据某厂振冲碎石桩加固液化砂土地基的工程实践及试验资料，对挤密碎石桩加固砂土地基的机理进行了探索，并通过分析，进一步证明该法对砂土地基的加固是卓有成效的．从振冲碎石桩加固砂土地基的加固原理和受力情况出发，扼要阐述了振冲碎石桩加固砂土地基的设计要点和施工工艺．     

采用振冲碎石桩加固饱和松散地基的实例

本文阐述了南京新华船舶修造厂轮机车间饱和砂土地基,如何通过振冲碎石桩加固而达到防止砂土的地震液化这一实例;并从加固前后碎石桩周围饱和砂土标准贯入度的变化来说明振冲碎石桩加固饱和砂土的效果及有效范围。     

某工程振冲碎石桩处理效果试验研究

结合某工程地基处理的实际,对可液化砂土运用振冲碎石桩处理后的抗液化性和提高承载力的效果进行了现场载荷试验。简述了振冲碎石桩设计指标的确定和施工参数的选择情况。根据现场试验结果,分析了该场地碎石桩复合地基的承载力和沉降性质。对该种可液化砂土应用碎石桩加固地基的效果给出了工程评价。试验结果表明,振冲碎石桩处理砂土液化效果较好,可满足工程要求。同时也为类似工程中的桩径、桩距、桩长、填料选择、施工参数的选取、检测方法设计等提供宝贵经验。     

和安花园振冲碎石置换桩消除砂土液化的经验

通过振冲置换碎石桩在处理液化地基中的工程实践,论述了振冲置换碎石桩法的施工工艺及处理效果,证明用于处理饱和砂土及粉土液化及提高地基上的承载力是可行的。     

振冲碎石桩在砂土地基处理中的应用及加固机理

介绍了振冲碎石桩法应用于地基加固处理的施工方法，从地基土的密实度、碎石桩体的排水效应等方面，分析了碎石桩复合地基的抗液化加固机理，提出了振冲碎石桩处理砂土地基的有效性。     

振冲法处理某闸基液化砂土工程应用效果分析

振冲法利用振冲器的强力振动和高压水冲加固土体,可以达到提高地基承载力、减小建筑物地基不均匀沉降、消除地基液化的目的.针对某闸在利用振冲碎石法消除饱和砂土液化问题时失效,介绍了振冲法在工程中的应用情况,从工程地质勘察、振冲处理设计、振冲施工3方面分析了振冲处理液化砂土效果,探讨了导致这种情况出现的原因,并得出结论.     

等能量等变形挤密碎石桩处理液化砂土的效果

等能量等变形挤密碎石桩是用相同的夯击能量和相同的贯入度控制桩体质量,使处理深度范围内地基土上下均匀。由于施工设备采用高能量实现孔内夯击填料,对桩底和桩间土施以振动和挤密,使松散砂土颗粒重新排列,可提高砂土的承载力和压缩模量及消除砂土的液化可能性。本工法在沿海高速路基工程的成功应用开辟了砂土液化处理的新途径,与振冲碎石桩的相比,该技术工艺先进、地基处理效果好、经济效益明显。     

振冲碎石桩在加固处理砂土液化地基中的应用

本文以福建沿海某道路工程砂土液化地基的加固处理为例,着重介绍了振冲碎石桩加固处理可液化地基的机理、技术参数及施工工艺。通过标准贯入试验、重型动力触探试验、载荷试验等原位测试方法,对桩间砂土层的液化消除效果、桩间砂土密实度、桩体施工质量及复合地基的承载性能进行了分析评价,试验所得结果可供类似工程借鉴。     

地震液化饱和砂土层内部超静孔压理论分析

本文利用土力学、土动力学及地下水动力学中的有关原理 ,对砂土液化发生机制进行分析 ,提出了液化临界超静孔隙水压力随地震持续时间及埋深等内外因素变化的关系 ,并利用该理论对唐山地区液化的特征进行了分析研究 ,并且与实际资料作了比较。     

Liquefaction analysis of sandy soil during strong earthquake in Northern Thailand

Northern Thailand has experienced several earthquakes which led to soil liquefaction in the past few decades. Traditional methods of evaluating liquefaction potential involve standard penetration test (SPT) or cone penetration tests. This research augmented experimental results with numerical methods to evaluate the liquefaction potential of Mae Lao Sand in Chiang Rai province of northern Thailand. SPT and downhole seismic test data collected during a field investigation at the Mae Lao site were compared to a 1D site response model analysis of the site. A series of undrained monotonic and cyclic triaxial tests was conducted on Mae Lao Sand specimens with different initial void ratios and confining pressures. Cyclic triaxial test results with varying deviator stress amplitudes were used to draw liquefaction resistance curves. Results from numerical simulation of sand liquefaction were used to characterise the stress–strain-pore water pressure response of Mae Lao Sand. 1D site response analysis determined seismic responses with different geological and groundwater conditions. All put together, the results showed that pore water pressure ratio decreases with increasing sand stiffness, the thickness of a soil layer significantly increases its liquefaction potential, and in-situ conditions and groundwater depths have major influences on the liquefaction potential of sand layers.     

砂土地震液化的模糊综合评判法

根据砂土液化问题具有的模糊性和不确定性,建立了一种判别砂土液化发生可能性的模糊综合评判模型。在提出的砂土液化模糊综合评判模型中,通过综合地震烈度、标贯击数、地下水位和平均粒径等影响砂土地震液化的因素,采用梯形隶属函数并分别给出各因素隶属函数的表达式。通过工程实例计算验证了该模型的可行性,计算过程简单明了,有一定的实用价值。     

Engineering geological characteristics of the 1998 Adana-Ceyhan earthquake, with particular emphasis on liquefaction phenomena and the role of soil behaviour

 The Adana-Ceyhan earthquake (M_s=6.2) occurred in the southern part of Turkey on 27 June 1998 and resulted in the loss of 145 lives and extensive damage to buildings in Ceyhan town and the settlement areas in its vicinity. Soil liquefaction, ground failure due to lateral spreading and rock falls occurred. The area of Adana is characterised by a large alluvial basin with a delta shape. Most of the basin is filled with Quaternary recent Holocene deposits. The recent rapid deposition of sediments and the very shallow groundwater table throughout the basin create conditions conducive to liquefaction. The results of a preliminary investigation of soil liquefaction caused by the earthquake and liquefaction assessments based on field performance data are presented together with evaluations concerning the likely contribution of the soils to the damage sustained by buildings. The results of the liquefaction susceptibility analysis indicated that the data from the liquefied sites were within the empirical bounds suggested by the field-performance evaluation method. It was also shown that shallow sand layers should have liquefied and the surface disruption observed on the site could be predicted by the bounds used for the relationships between the thickness of liquefiable sediments and the overlying non-liquefiable soil. Site-response analyses based on acceleration response spectra from the actual earthquake's strong motion records revealed that soil behaviour was one of the most significant factors in the damage to buildings caused by the earthquake. Received: 4 January 2000 · Accepted: 28 March 2000     

松原5.7级地震砂土液化研究

2018年5月28日吉林省松原市宁江区发生M5.7级地震,震中地区出现典型罕见的大范围砂土液化现象。通过震害现场调查,结合钻探取样、标贯试验、波速测试及静力触探等试验测试手段,查明震害情况和场地特性,初步分析此次大范围砂土液化的形成条件和影响因素。调查结果表明,此次地震液化区域面积约80km2,宏观现象主要以水稻田内表喷水冒砂为主,未造成建筑物大规模破坏,且区域内土层分布相对单一,液化分布主要受地震动、地形地貌及地下水位等因素控制;液化土层埋深主要在10m以内,并且钻探揭露一处埋深17m左右黏土层中的液化砂土上升通道,证明本次地震中出现明显的深层砂土液化现象,该现象在地震现场调查往往被忽略;静力触探在鉴别液化层位、获取土层物理力学参数上具有一定优势,较适用于震后现场调查工作。另外,松原市具有发生更大规模砂土液化的可能性,在防震减灾规划及建设工程勘察设计等项目中,对该地区的砂土液化情况需进行专门研究。     

某越江通道工程江中风井抗震稳定性研究

针对江中建（构）筑物在强震影响下的主要危害多为地基液化和建（构）筑物开裂的特点,作者对某越江通道工程江中风井的地基地震液化和井体稳定性进行了分析,并根据其场地资料和井体资料采用拟静力法和数值模拟对在7度地震烈度下的地基液化势和井体稳定性进行了计算分析。结果表明：在7度地震烈度下,风井是稳定的。     

胜利—果园村液化带工程地质条件及液化土层特性分析

砂土液化是地震主要次生地质灾害之一,其是否发生及液化程度如何与地层结构、地下水、土层类型及特征等工程地质条件密切相关,通常饱和砂土和饱和粉土容易发生液化。5.12汶川地震中,在以砾石为主要地层的德阳等地发生了严重的砂土液化现象,这在以往地震中少见。胜利—果园村液化带是德阳地区诸多典型液化带之一,通过现场钻探和试验表明:液化带主要土层为砾石和粘土,发生液化的土层为全新统砾石层;液化砾石层结构松散,颗粒大小分布曲线较平缓,平均粒径和不均匀系数较大,曲率系数较小;地面喷出物是粗砂,其颗粒组成与液化砾石层相差很大。     

地下水水位对饱和砂土震动液化判定的影响

结合荆州市某商业广场地基工程实例,从标准贯入试验、静力触探试验、剪切波速试验和计算等方面就地下水水位对饱和砂土震动液化判定的影响等问题进行论证分析。建议取承压水水头深度作为地下水水位深度来进行饱和砂土震动液化的判定。     

轻型井点降水＋强夯法在消除砂土液化中应用

结合某主厂区主装置区场地地基处理试验施工工程,针对其场地区上部素填土、淤泥质黏土、下部粉细砂的地基条件,对采用轻型井点降水联合强夯法消除砂土液化进行了试验分析研究。根据试验施工检测结果,验证了各土层的加固效果,从而说明轻型井点降水联合强夯法消除砂土液化行之有效。