MODEL TESTS ON LATERAL BEARING BEHAVIOR OF SINGLE ENERGY PILE IN SAND
-
摘要:
为探究能量桩单桩水平承载特性，针对砂土中能量桩在水平荷载下的承载特性进行研究，基于模型试验，分析了水平荷载作用下能量桩在制冷和加热过程中的桩顶位移、桩前土压力以及桩身弯矩等的变化规律。研究结果表明：制冷会引起能量桩桩顶水平位移略微增大，增量为0.48%D(D为桩体直径)，而加热会引起较大的桩顶水平位移，达到了2.38%D；制冷和加热在初始阶段会引起桩前土压力增大，初始增长阶段结束后，土压力变化较小，多为缓慢增长或基本不变。相较于初始土压力，制冷和加热结束时的土压力基本呈增长趋势，仅个别埋深处土压力减小。制冷过程中，埋深0%L~40%L(L为有效桩长)范围内的弯矩增大，埋深40%L~100%L位置处的弯矩变化较小；加热过程中，埋深0%L~60%L范围内的弯矩均有所增大，0%L~40%L位置处的弯矩增大最为明显。制冷和加热过程中均在20%L处产生了最大弯矩，最大弯矩的增加量分别为9.93%和10.32%。进一步基于圆孔扩张理论提出了弯矩计算的理论解，并与试验结果进行对比分析，理论计算值与实测值较为吻合。
Abstract:In order to explore the lateral bearing characteristic of single energy piles, the bearing behavior of energy piles subjected to lateral load in sand is studied. Based on model tests, the pile top displacement, the soil pressure in front of the pile, and the bending moment during cooling and heating of the energy pile subjected to lateral load are analyzed. The results show that cooling process will slightly increase the pile top lateral displacement by 0.48%D (D is the pile diameter). The heating process will also significantly increase the pile top lateral displacement, and the increment reaches 2.38%D. In the initial stage cooling and heating, the soil pressure in front of the pile will increase, and after the initial stage, the change of pressure is small with slow or no increment. The horizontal soil pressure increases generally after cooling and heating, and the pressure decrease is observed only at a few points. After cooling, the pile bending moment at the depth of 0%L ~ 40%L (L is the effective pile length) will increase, while the bending moment at the depth of 40%L ~ 100%L will have less change. During heating, the bending moment at the depth of 0%L ~ 60%L will increase significantly, and the bending moment at the depth of 0%L ~ 40%L has the most obvious increase. The maximum bending moments during heating and cooling are both produced at the depth of 20%L, and the increment reaches 9.93% and 10.32% respectively. Based on the cavity expansion theory, the theoretical solution of the bending moment is proposed. Compared with the experimental results, the calculated values are in good agreement with the measured values.
-
Keywords:
- energy pile /
- lateral bearing behavior /
- model tests /
- sand /
- cavity expansion theory
-
-
![]()
图 2 换热管实物图及示意图
Figure 2. Physical diagram and schematic diagram of heat exchanger tube
![]()
图 7 制冷和加热时桩顶水平位移的变化规律
Figure 7. Horizontal displacement of pile top during heating and cooling
![]()
图 8 制冷和加热时桩前土压力的变化规律
Figure 8. Horizontal soil pressure in front of the pile during heating and cooling
表 1 模型试验砂土物理参数
Table 1 Physical parameters of sand in model tests
土粒比重 天然密度/(g·cm−3) 天然含水率/(%) 干密度/(g·cm−3) 最小干密度/(g·cm−3) 最大干密度/(g·cm−3) 摩擦角/(°) D10/mm D30/mm D60/mm Cc Cu 2.67 1.58 4.63 1.51 1.47 1.75 31.1 0.26 0.61 1.13 1.10 4.35 注：1) D10、D30、D60分别为累计粒度分布数达到10%、30%、60%时所对应的粒径；2) Cc和Cu分别为砂土的曲率系数和不均匀系数。 
下载: 导出CSV
表 2 EP1、EP2和EP3的试验方案
Table 2 Test of EP1、EP2 and EP3
桩体 水平荷载 通水温度/(℃) 室温/(℃) 温度变化/(℃) EP1 极限荷载 无 25 无 EP2 工作荷载 10 25 −15 EP3 工作荷载 40 25 +15
下载: 导出CSV
-
[1] BRANDL H. Energy foundations and other thermo-active ground structures [J]. Géotechnique, 2006, 56(2): 81 − 122.
[2] WU D, LIU H, KONG G, et al. Interactions of an energy pile with several traditional piles in a row [J]. Journal of Geotechnical and Geoenvironmental Engineering, 2020, 146(4): 06020002. doi: 10.1061/(ASCE)GT.1943-5606.0002224
[3] MORADSHAHI A, FAIZAL M, BOUAZZA A, et al. Cross-sectional thermo-mechanical responses of energy piles [J]. Computers and Geotechnics, 2021, 138: 104320. doi: 10.1016/j.compgeo.2021.104320
[4] FAIZAL M, BOUAZZA A, HABERFIELD C, et al. Axial and radial thermal responses of a field-scale energy pile under monotonic and cyclic temperature changes [J]. Journal of Geotechnical and Geoenvironmental Engineering, 2018, 144(10): 04018072. doi: 10.1061/(ASCE)GT.1943-5606.0001952
[5] FAIZAL M, BOUAZZA A, SINGH R M. An experimental investigation of the influence of intermittent and continuous operating modes on the thermal behaviour of a full scale geothermal energy pile [J]. Geomechanics for Energy and the Environment, 2016, 8: 8 − 29. doi: 10.1016/j.gete.2016.08.001
[6] 陆浩杰, 吴迪, 孔纲强, 等. 循环温度作用下饱和黏土中摩擦型桩变形特性研究[J]. 工程力学, 2020, 37(5): 156 − 165. doi: 10.6052/j.issn.1000-4750.2019.07.0353 LU Haojie, WU Di, KONG Gangqiang, et al. Displacement characteristics of friction piles embedded in saturated clay subjected to thermal cycles [J]. Engineering Mechanics, 2020, 37(5): 156 − 165. (in Chinese) doi: 10.6052/j.issn.1000-4750.2019.07.0353
[7] WU D, LIU H L, KONG G Q, et al. Displacement response of an energy pile in saturated clay [J]. Proceedings of the Institution of Civil Engineers-Geotechnical Engineering, 2018, 171(4): 285 − 294. doi: 10.1680/jgeen.17.00152
[8] LIU H L, WANG C L, KONG G Q, et al. Ultimate bearing capacity of energy piles in dry and saturated sand [J]. Acta Geotechnica, 2019, 14(3): 869 − 879. doi: 10.1007/s11440-018-0661-6
[9] 王成龙, 刘汉龙, 孔纲强, 等. 不同刚度约束对能量桩应力和位移的影响研究[J]. 岩土力学, 2018, 39(11): 4261 − 4268. doi: 10.16285/j.rsm.2017.0352 WANG Chenglong, LIU Hanlong, KONG Gangqiang, et al. Study on stress and displacement of energy pile influenced by pile tip stiffness [J]. Rock and Soil Mechanics, 2018, 39(11): 4261 − 4268. (in Chinese) doi: 10.16285/j.rsm.2017.0352
[10] 王成龙, 刘汉龙, 孔纲强, 等. 不同埋管形式下能量桩热力学特性模型试验研究[J]. 工程力学, 2017, 34(1): 85 − 91. doi: 10.6052/j.issn.1000-4750.2015.05.0455 WANG Chenglong, LIU Hanlong, KONG Gangqiang, et al. Model tests on thermal mechanical behavior of energy piles influenced with heat exchangers types [J]. Engineering Mechanics, 2017, 34(1): 85 − 91. (in Chinese) doi: 10.6052/j.issn.1000-4750.2015.05.0455
[11] NG C W W, SHI C, GUNAWAN A, et al. Centrifuge modelling of heating effects on energy pile performance in saturated sand [J]. Canadian Geotechnical Journal, 2015, 52(8): 1045 − 1057. doi: 10.1139/cgj-2014-0301
[12] ZHAO R, LEUNG A K, KNAPPETT J A. Thermally induced ratcheting of a thermo-active reinforced concrete pile in sand under sustained lateral load [J]. Géotechnique, 2022. doi: 10.1680/jgeot.21.00299.
[13] VITALI D, LEUNG A K, FENG S, et al. Centrifuge modelling of the use of discretely spaced energy pile row to reinforce unsaturated silt [J]. Géotechnique, 2022, 72(7): 618 − 631.
[14] HEIDARI B, GARAKANI A A, JOZANI S M, et al. Energy piles under lateral loading: Analytical and numerical investigations [J]. Renewable Energy, 2022, 182: 172 − 191. doi: 10.1016/j.renene.2021.09.125
[15] DUPRAY F, LI C, LALOUI L. Heat-exchanger piles for the de-icing of bridges [J]. Acta Geotechnica, 2014, 9(3): 413 − 423. doi: 10.1007/s11440-014-0307-2
[16] ZDRAVKOVIC L, TABORDA D M G, POTTS D M, et al. Numerical modelling of large diameter piles under lateral loading for offshore wind applications [C]// Proceedings of the 3rd International Symposium on Frontiers in Offshore Geotechnics. Oslo: CRC Press, 2015, 1: 759 − 764.
[17] KRAMER C A, GHASEMI-FARE O, BASU P. Laboratory thermal performance tests on a model heat exchanger pile in sand [J]. Geotechnical and Geological Engineering, 2015, 33(2): 253 − 271. doi: 10.1007/s10706-014-9786-z
[18] 杨克己, 李启新, 王福元. 水平力作用下群桩性状的研究[J]. 岩土工程学报, 1990, 12(3): 42 − 52. doi: 10.3321/j.issn:1000-4548.1990.03.005 YANG Keji, LI Qixin, WANG Fuyuan. Study on behavior of pile groups under lateral load [J]. Chinese Journal of Geotechnical Engineering, 1990, 12(3): 42 − 52. (in Chinese) doi: 10.3321/j.issn:1000-4548.1990.03.005
[19] NG C W W, WANG S H, ZHOU C. Volume change behaviour of saturated sand under thermal cycles [J]. Géotechnique Letters, 2016, 6(2): 124 − 131.
[20] 孙毅龙, 许成顺, 杜修力, 等. 海上风电大直径单桩的修正p-y曲线模型[J]. 工程力学, 2021, 38(4): 44 − 53. doi: 10.6052/j.issn.1000-4750.2020.01.0051 SUN Yilong, XU Chengshun, DU Xiuli, et al. A modified p-y curve model of large-monopiles of offshore wind power plants [J]. Engineering Mechanics, 2021, 38(4): 44 − 53. (in Chinese) doi: 10.6052/j.issn.1000-4750.2020.01.0051
[21] 黄申, 翟恩地, 许成顺, 等. 考虑附加抗力影响的单桩水平受力分析方法[J]. 工程力学, 2022, 39(6): 156 − 168. doi: 10.6052/j.issn.1000-4750.2021.03.0227 HUANG Shen, ZHAI Endi, XU Chengshun, et al. A method of analyzing laterally loaded monopiles considering the influence of additional resistance [J]. Engineering Mechanics, 2022, 39(6): 156 − 168. (in Chinese) doi: 10.6052/j.issn.1000-4750.2021.03.0227
[22] 张小玲, 赵景玖, 孙毅龙, 等. 基于圆孔扩张理论的桩基水平承载力计算方法[J]. 工程力学, 2021, 38(2): 232 − 241, 256. doi: 10.6052/j.issn.1000-4750.2020.04.0278 ZHANG Xiaoling, ZHAO Jingjiu, SUN Yilong, et al. An analysis method for the horizontal bearing capacity of pile foundation based on the cavity expansion theory [J]. Engineering Mechanics, 2021, 38(2): 232 − 241, 256. (in Chinese) doi: 10.6052/j.issn.1000-4750.2020.04.0278
[23] 梅国雄, 宰金珉. 考虑变形的朗肯土压力模型[J]. 岩石力学与工程学报, 2001, 20(6): 851 − 854. doi: 10.3321/j.issn:1000-6915.2001.06.022 MEI Guoxiong, ZAI Jinmin. Rankine earth pressure model considering deformation [J]. Chinese Journal of Rock Mechanics and Engineering, 2001, 20(6): 851 − 854. (in Chinese) doi: 10.3321/j.issn:1000-6915.2001.06.022
[24] YAVARI N, TANG A M, PEREIRA J M, et al. Effect of temperature on the shear strength of soils and the soil-structure interface [J]. Canadian Geotechnical Journal, 2016, 53(7): 1186 − 1194. doi: 10.1139/cgj-2015-0355
[25] MURAYAMA S. Effect of temperature on elasticity of clays [C]// Proceedings of an International Conference Held at Washington, D. C., January 16 1969 With the Support of the National Science Foundation. Washington: Highway Research Board, 1969: 194 − 203.
[26] LAGUROS J G. Effect of temperature on some engineering properties of clay soils [C]// Proceedings of an International Conference Held at Washington, D. C., January 16 1969 With the Support of the National Science Foundation. Washington: Highway Research Board, 1969: 186 − 193.
计量
- 文章访问数: 178
- HTML全文浏览量: 62
- PDF下载量: 43
