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   

侧限压缩下砂土的细观力学特性及其形态分析   总被引：1，自引：0，他引：1       下载免费PDF全文

曹亮  刘文白  李晓昭  赵晓豹  张辉 《地质论评》2011,57(4):591-599

本文基于室内固结试验,自行设计加工了土体受到轴向压力和侧限条件时,对土的细观结构进行观测的细观结构观测固结仪.通过对中砂半模固结仪试验的宏观变形场分析选择了细观特征观测点,发现中砂的位移场类似于抛物线形,位移量最大区总是发生在上透水石的底面中心处;利用MiFas图像软件对中砂压缩过程中的显微图像进行处理,分析了中砂试样...  相似文献   

柴木铁路沼泽化冻土区热管冷却半径的观测研究     

陈继  徐舜华  窦顺  张鲁新 《冰川冻土》2011,33(4):897-901

柴达尔-木里铁路沿线高温沼泽化多年冻土广泛发育,约20km的冻土路基采用了热管降温措施．借鉴青藏铁路的成功经验,热管的纵向和横向间距均设计为3m,并针对铁路东南-西北的不利走向,在阳坡布设了双排热管．为验证热管措施在多年冻土湿地路段设计参数的合理性,2008年底在柴达尔-木里铁路中段布设了热管冷却半径观测试验场,该观测...  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   

苏通大桥超长桩桩底后压浆试验及效果          下载免费PDF全文

彭仕奇 《探矿工程》2011,38(11):54-58

在苏通大桥松散软弱的地层条件,实施超长（〉100 m）、超大（2.5 m）摩擦桩桩底后压浆工程,在我国是首次运用。结合工程实践,就压浆工程的设计、施工的技术要点进行全面介绍。通过对钻孔取样分析,指出浆液初凝时间地表实验与地下实际存在较大差异;通过施工体验,结合取样显示的浆液扩散渗透状况,提出可渗透地层以注浆量为控制参数,压力不列为控制参数的思路。  相似文献   

旋挖钻机与冲击钻机组合在嵌岩桩施工中的应用          下载免费PDF全文

孙琦  仲文涛  李玉成 《探矿工程》2011,38(8):50-52

旋挖钻机施工工艺和正循环冲击钻机施工工艺相结合,充分发挥了旋挖钻机施工土层速度快和正循环冲击钻机施工岩层速度快的优点,从而打破嵌岩桩施工的传统工艺,为大口径嵌岩桩施工提供经验和技术参考。通过镇江市体育会展中心体育场桩基工程采用旋挖钻机施工工艺和正循环冲击钻机组合成孔工艺的成功实例,介绍了该工艺的施工技术措施及注意要点。  相似文献   

娄江特大桥深孔泵吸反循环工艺的改进          下载免费PDF全文

张广亮  刘建涛  陈益敏 《探矿工程》2011,38(6):47-50

随着国家基础设施投入的加大,桩径1000－2000 mm、孔深100－130 m的钻孔灌注桩在各类工程中屡被采用。泵吸反循环传统上被用于孔深不超过80 m的深孔,在京沪高铁第六标段娄江特大桥钻孔灌注桩施工中,通过对现有的反循环钻机进行改进,很大程度上提高了泵吸反循环的工作效率,顺利地完成了孔深131 m、桩径1.8 m桩孔的施工,产生了很好的经济效益。  相似文献   

复杂地质条件下组合围堰施工   总被引：2，自引：0，他引：2       下载免费PDF全文

王海龙  李飞  夏亚飞 《探矿工程》2011,38(3):64-67

在复杂的地质条件下,根据现场地质情况选择合理的围堰成为深基坑开挖过程中支护与止水的关键。结合柳州双拥大桥22号墩主塔基础施工,介绍了采用锁口钢管桩与钢筋混凝土支护桩相结合的组合围堰来进行复杂地质条件下的围堰施工技术。  相似文献   

超长细桩成孔垂直度施工控制          下载免费PDF全文

张军旗  任世校  赵丽 《探矿工程》2011,38(1):66-67

通过天津高银商务区117主塔楼基础桩施工实践,就超长细桩成孔垂直度控制问题进行试验、研究,提出一些具体的控制措施,总结了施工经验和体会。  相似文献