免共振沉桩过程对地表振动影响的FLAC3D数值模拟     

魏家斌  王卫东  吴江斌 《吉林大学学报(地球科学版)》2021,51(5):1514-1522

为研究免共振沉桩过程对地表振动影响,采用密度放大法以消除模型桩弹性模量过大对计算效率的影响,在有限差分软件FLAC^3D中建立了相应的连续振动沉桩模型,并和文献中的现场测试结果进行了比较,分析了激振力幅值和振动频率这两个施工参数对地表振动响应的影响。结果表明：密度放大法可有效提高数值模拟的计算效率,模拟沉桩7.0倍桩径（4.9 m）所需计算时间约为12.0 h,数值结果较好地模拟了现场测试中免共振沉桩的地表振动影响;激振力幅值和振动频率均主要对近场（水平距离为5.0倍桩径范围内）的地表振动有明显影响;临界沉桩深度与地表振动影响峰值相对应,该深度随水平距离先增大后趋于稳定;激振力幅值对临界沉桩深度的改变不明显,振动频率对远场临界沉桩深度则有较明显影响。  相似文献   

超大超深灌注桩施工关键技术研究与应用     

刘金森  高慧广  朱神松  吴小勇 《中国煤炭地质》2021,(3):25-27

以深圳某项目桩基础施工为依托,综合考虑地质特点和施工工艺要求,对超大超深灌注桩在花岗岩地层施工开展了相关研究,并将研究成果应用到实际施工中,有效地解决了该类型桩基础施工中的难点,保证了项目的顺利实施,为后续类似项目提供了参考依据。  相似文献   

螺杆桩技术设计与施工在长春地区的应用     

李国峰  张德新 《吉林地质》2011,30(3):112-115

本文利用螺杆桩技术对长春地区粘性土层,进行抗拔实验,获得螺杆桩在粘性土层中抗拔承载力值,通过现场抗拔桩试验检测,为螺杆桩技术在长春地区应用提供理论依据,具有重要的理论与实际意义。  相似文献   

舟曲泥石流桩林拦挡结构抗冲压极限分析   总被引：1，自引：0，他引：1  

李瑞冬  马宗源  胡向德 《甘肃地质》2011,(2):60-65

以舟曲泥石流灾害防治工程为背景,基于弹塑性有限差分方法计算分析了舟曲泥石流桩林拦挡结构的极限抗冲压能力。针对两种桩林拦挡结构设计方案,采用增量加载的数值计算方法确定了拦挡结构的侧向极限抗冲压力,并与规范建议的泥石流冲击力经验公式计算结果进行了校核。计算结果显示,舟曲泥石流桩林拦挡结构的侧向极限抗冲压力均大于经验公式计算...  相似文献   

桩端加环对PHC桩影响的试验研究     

陈亮 《岩土工程技术》2011,25(1):5-9,37

PHC桩在动力打桩过程中,往往会因为锤击数或锤击能量过高而发生桩头或桩身损坏,引起的挤土效应和振动效应也会对周围环境造成不良影响.PHC桩桩端加环可减少沉桩过程中桩侧土体摩阻力的影响,结合某电厂工程综合试桩工作,通过对沉桩总锤击数、最终贯入度、土塞高度、打桩振动测试及高应变检测结果的分析,指出桩端加环对保证PHC桩的完...  相似文献   

抗拔桩变形分析与有效桩长预测   总被引：1，自引：0，他引：1  

郑大龙 《上海国土资源》2011,32(2):75-78

以抗拔桩变形的理论分析为基础,选择双曲线荷载传递函数对桩的极限侧阻力进行合理取值,通过迭代法得到桩身受力情况,由此预测抗拔桩的＂有效桩长＂。结合工程实例进行了计算验证,证明该方法具有实用价值和推广意义。  相似文献   

Finite element analysis on impact of foundation treatment in bridgehead transition section upon bridge piles          下载免费PDF全文

ZHENG Wei  DU Lizhi  WANG Yong 《世界地质(英文版)》2011,14(4):254-258

In order to decrease relative settlement, foundation treatment plays an extremely important role in bridgehead transition section, especially, the situation of building the bridge piles firstly, and th...  相似文献   

Thermal analysis of energy piles in sand     

Rajni Saggu 《Geomechanics and Geoengineering》2015,10(1):10-29

The present work investigates the behaviour of geothermal energy piles in sand subjected to thermal loading and the resulting soil-structure interaction, numerically using the finite element software Abaqus and user-defined material subroutines for soil. The stress-strain response of sand has been simulated using CASM constitutive model based on critical-state soil mechanics. Detailed parametric sensitivity studies have been carried out to understand the effects of different end conditions of the pile, relative densities of the soil, coefficients of lateral earth pressure of the ground, lengths and diameters of the pile, thermal loads, coefficients of friction at the pile-soil interface, critical-state friction angles of soil, thermal conductivity of soil, specific heat of soil and thermal conductivity of the pile on the stress response of soil, deformation of the pile and soil, and strains in the pile. The results show that negative shear stress is generated in the soil at the pile-soil interface. In the pile with both ends restrained the lateral earth pressure coefficient in soil increases due to high radial strain generation. Moreover, the lateral earth pressure coefficient in soil increases with the increase in the thermal load, the coefficient of friction at the pile-soil interface and the critical-state friction angle of the soil.  相似文献   

Numerical simulations and parametric study of SDCM and DCM piles under full scale axial and lateral loads     

Panich Voottipruex  Taweephong Suksawat  D.T. Bergado  Pitthaya Jamsawang 《Computers and Geotechnics》2011

The new kind of reinforced Deep Cement Mixing (DCM) pile namely, Stiffened Deep Cement Mixing (SDCM) pile is introduced to mitigate the problems due to the low flexural resistance, quality control problem and unexpected failure of DCM pile. The SDCM pile consists of DCM pile reinforced with concrete core pile. Previously, the full scale pile load test and the full scale embankment loading test were successfully conducted in the field. To continue the study on the behavior of SDCM and DCM piles, the 3D finite element simulations using PLAXIS 3D Foundation Software were conducted in this study. The simulations of full scale pile load test consisted of two categories of testing which are the axial compression and the lateral loading. For DCM C-1 and C-2 piles, the clay–cement cohesion, C_DCM, and clay–cement modulus, E_DCM, were obtained from simulations as 300 kPa and 200 kPa as well as 60,000 kPa and 40,000 kPa, respectively. For the SDCM piles, the simulation results show that increasing length ratio, L_core/L_DCM, increased the bearing capacity whereas the sectional area ratio, A_core/A_DCM, has only small effects on the bearing capacity for the axial compression loading. The verified parameters such as the clay–cement cohesion, C_DCM, and clay–cement modulus, E_DCM, from simulations of axial compression tests were 200 kPa and 30,000 kPa, respectively. On the other hand, increasing the sectional area ratio, A_core/A_DCM, significantly influenced the ultimate lateral resistance while the length ratio, L_core/L_DCM, is not significant in the ultimate lateral load capacity when the length of concrete core pile is longer than 3.5 m. In addition, the tensile strength of DCM, T_DCM, and concrete core pile, T_core, are very important to the lateral pile resistance. The back-calculation results from simulations of tensile strength were 5000 kPa and 50 kPa for the T_core and T_DCM, respectively.  相似文献   

提高钻孔桩桩底压浆工效及保证质量的技术措施          下载免费PDF全文

刘宝新  唐世杰  陈跃武 《探矿工程》2011,38(10):56-59

钻孔桩桩底压浆技术是向钻孔灌注桩桩底沉渣和围岩土体内压入一定量水泥浆,使桩底沉渣和桩底一定范围土体孔隙内充满水泥浆液,经物理、化学作用使其强度大幅提高,从而实现单桩竖向承载力的提高。结合高铁钻孔桩桩底压浆施工实践,介绍了2种压浆工艺过程,阐明了提高压浆工效、保证注浆质量关键技术措施实施的重要性。  相似文献