Experimental study on simulated driven pile and immersion static load in undisturbed mudstone
BAI Xiaoyu1，2，ZHANG Yamei1，2，YIN Jichao1，2，WANG Yonghong1，2，SANG Songkui1，2，YAN Nan1，2
(1. College of Civil Engineering，Qingdao University of Technology，Qingdao，Shandong 266520，China；2. Shandong Provincial Colleges and Universities Blue Economic Zone Engineering Construction and Safety Collaborative Innovation
Center，Qingdao University of Technology，Qingdao，Shandong 266520，China)
Abstract：In order to study the bearing capacity of dynamic driving pile in mudstone foundation，the influence of driving process and water on the mechanical properties of mudstone is considered. The model tests of pile driving and static load，needle penetration test and electronic magnifying glass test were carried out. Combined with the field test data，the penetration characteristics and bearing capacity of the driven pile are analyzed，and the damage characteristics of mudstone around the pile are clarified. The results shows that：(1) the mudstone has strong heterogeneity，and the soft and hard interbedded phenomenon is significant. The maximum strength is 13.5 times of the minimum value，and the variation trend of mudstone strength and hammering number is synchronous. (2) The strength of the mudstone at the soft interlayer decreases by 64.2% on average after immersion，and the static load test is damaged by large settlement at the soft interlayer，and the steep drop characteristics are the same as the field test. (3) The damage range of pile driving is 2d(d is pile diameter). The strength of mudstone decreases by 66%，40.5%，17% and 7% on average in 0‐0.5d，0.5d‐1.0d，1.0d‐1.5d and 1.5d‐2.0d around the pile. (4) There is compaction relaxation phenomenon at the pile end. The strength of mudstone at the pile end is 11.1% higher than that at 2d around the pile，and 194.5 % higher than that at the same position of the pile. (5) Mudstone heterogeneity is the cause of mudstone pile bearing capacity problem，which is easy to be ignored in geologic investigation. It is considered that mudstone is always uniform，stable，and its strength increases with depth. This phenomenon should be recognized and paid attention to.
[1] 张明义，时 伟，章 伟，等. 地基基础工程[M]. 北京：科学出版社，2017：1–3.(ZHANG Mingyi，SHI Wei，ZHANG Wei，et al. Foundation engineering[M]. Beijing：Science Press，2017：1–3.(in Chinese))
[2] 罗春雷，顾增海，喻 威，等. 基于地基特性的双作用液压锤沉桩可打入性研究[J]. 中南大学学报：自然科学版，2015，46(10)：3 663–3 669.(LUO Chunlei，GU Zenghai，YU Wei，et al. Drivability of piles by double-process hydraulic hammer based on geological characteristics[J]. Journal of Central South University：Science and Technology，2015，46(10)：3 663–3 669.(in Chinese))
[3] 苗德滋，张明义，白晓宇，等. 青岛地区嵌岩打入桩工程质量分析[J]. 工程勘察，2018，46(9)：1–5.(MIAO Dezi，ZHANG Mingyi，BAI Xiaoyu，et al. Engineering quality analysis of rock-socketed driven pile in Qingdao area[J]. Geotechnical Investigation and Surveying，2018，46(9)：1–5.(in Chinese))
[4] 柳万里，晏鄂川，戴 航，等. 巴东组泥岩水作用的特征强度及其能量演化规律研究[J]. 岩石力学与工程学报，2020，39(2)：311–326.(LIU Wanli，YAN Echuan，DAI Hang，et al. Study on characteristic strength and energy evolution law of Badong formation mudstone under water effect[J]. Chinese Journal of Rock Mechanics and Engineering，2020，39(2)：311–326.(in Chinese))
[5] 曾 铃，张华麟，戚双星，等. 基于能量耗散原理的炭质泥岩崩解特征试验研究[J]. 中南大学学报：自然科学版，2021，52(11)：4 181–4 189.(ZENG Ling，ZHANG Hualin，QI Shuangxing，et al. Experimental study on disintegration characteristics of carbonaceous mudstone based on energy dissipation principle[J]. Journal of Central South University：Science and Technology，2021，52(11)：4 181–4 189.(in Chinese))
[6] 傅旭东，卢继忠，黄 斌，等. 含软弱夹层的强风化泥岩强度及破坏模式试验研究[J]. 东南大学学报：自然科学版，2021，51(2)：242–248.(FU Xudong，LU Jizhong，HUANG Bin，et al. Experimental study on strength and failure mode of strongly weathered mudstone with weak interlayer[J]. Journal of Southeast University：Natural Science，2021，51(2)：242–248.(in Chinese))
[7] 吴江斌，王卫东，陈 锴. 438 m武汉中心大厦嵌岩桩设计[J]. 岩土工程学报，2013，35(增1)：76–81.(WU Jiangbin，WANG Weidong，CHEN Kai. Design of socketed piles for 438 m-high Wuhan Center Building[J]. Chinese Journal of Geotechnical Engineering，2013，35(Supp.1)：76–81.(in Chinese))
[8] 牟洋洋，白晓宇，张明义. 强风化泥岩地基上CFG桩复合地基应用与优化[J]. 建筑结构，2019，49(12)：120–124.(MOU Yangyang，BAI Xiaoyu，ZHANG Mingyi. Application and optimization of CFG pile composite foundation on strong weathered mudstone foundation[J]. Building Structure，2019，49(12)：120–124.(in Chinese))
[9] 张先伟，李仁耿. 预应力管桩桩端土遇水软化研究[C]// 中国土木工程学会2016年学术年会论文集. [S. l.]：[s. n.]，2016：369–379.(ZHANG Xianwei，LI Rengeng. Study on bearing stratum softening of prestressed concrete tube pile when encountering water[C]// Proceedings of the 2016 Academic Annual Conference of the Chinese Society of Civil Engineering. [S. l.]：[s. n.]，2016：369–379. (in Chinese))
[10] 郭金雪，刘金波，张 松，等. 预应力管桩承载力不满足要求原因分析与处理方法[J]. 施工技术，2021，50(12)：96–99.(GUO Jinxue，LIU Jinbo，ZHANG Song，et al. Cause analysis and treatment method of insufficient bearing capacity of prestressed pipe pile[J]. Construction Technology，2021，50(12)：96–99.(in Chinese))
[11] 张信贵，易念平. 南宁盆地泥岩特性与工程桩基失效探析[J]. 岩土力学，2006，27(增2)：1 273–1 276.(ZHANG Xingui，YI Nianping. Analysis of causes to invalidate bored piles on a base of shallow mudstone in Nanning basin[J]. Rock and Soil Mechanics，2006，27(Supp.2)：1 273–1 276.(in Chinese))
[12] 程 晔，龚维明，戴国亮，等. 软岩桩基承载性能试验研究[J]. 岩石力学与工程学报，2009，28(1)：165–172.(CHENG YE，GONG Weiming，DAI Guoliang，et al. Research on bearing performance of socketed pile in soft rock[J]. Chinese Journal of Rock Mechanics and Engineering，2009，28(1)：165–172.(in Chinese))
[13] 张先伟，李仁耿，郑永民，等. 顺德强风化岩层预应力管桩桩端土软化的现场试验研究[J]. 中国科学：技术科学，2016，46(9)：975–986.(ZHANG Xianwei，LI Rengeng，ZHENG Yongmin，et al. Field experimental study on prestressed concrete tube-pile bearing stratum softening in strong weathered rock formation of Shunde area[J]. Scientia Sinica Technologica，2016，46(9)：975–986.(in Chinese))
[14] 何满潮，周 莉，李德建，等. 深井泥岩吸水特性试验研究[J]. 岩石力学与工程学报，2008，27(6)：1 113–1 120.(HE Manchao，ZHOU Li，LI Dejian，et al. Experimental research on hydrophilic characteristics of mudstone in deep well[J]. Chinese Journal of Rock Mechanics and Engineering，2008，27(6)：1 113–1 120.(in Chinese))
[15] CHONG W L，HAQUE A，GAMAGE R P，et al. Modelling of intact and jointed mudstone samples under uniaxial and triaxial compression[J]. Arabian Journal of Geosciences，2013，6(5)：1 639–1 646.
[16] 马福荣，张信贵，易念平. 取样卸荷对膨胀性泥岩强度与变形特性影响的试验研究[J]. 水利水运工程学报，2017，(5)：109–116.(MA Furong，ZHANG Xingui，YI Nianping. Experimental study of unloading impact on deformation behavior and strength of mudstone in sampling state[J]. Hydro-Science and Engineering，2017，(5)：109–116.(in Chinese))
[17] JING H，YIN Q，YANG S，et al. Micro-mesoscopic creep damage evolution and failure mechanism of sandy mudstone[J]. International Journal of Geomechanics，2021，21(3)：04021010.
[18] 韩 强，屈 展，叶正寅. 基于均匀化理论的页岩微观多孔黏土强度特性[J]. 力学学报，2019，51(3)：940–948.(HAN Qiang，QU Zhan，YE Zhengyin. Study on strength characteristics of microporous clay in shale based on homogenization theory[J]. Chinese Journal of Theoretical and Applied Mechanics，2019，51(3)：940–948.(in Chinese))
[19] 李桂臣，李菁华，孙元田，等. 泥岩多尺度模型与水岩作用特性研究进展[J]. 煤炭学报，2022，47(3)：1 138–1 154.(LI Guichen，LI Jinghua，SUN Yuantian，et al. Advance of multi-scale study on both analytic models and water-rock interaction characteristics of mudstone[J]. Journal of China Coal Society，2022，47(3)：1 138–1 154. (in Chinese))
[20] 刘长武，陆士良. 泥岩遇水崩解软化机制的研究[J]. 岩土力学，2000，21(1)：28–31.(LIU Changwu，LU Shiliang. Research on mechanism of mudstone degradation and softening in water[J]. Rock and Soil Mechanics，2000，21(1)：28–31.(in Chinese))
[21] 王育兴，孙 钧. 打桩施工对周围土性及孔隙水压力的影响[J]. 岩石力学与工程学报，2004，23(1)：153–158.(WANG Yuxing，SUN Jun. Influence of pile driving on properties of soils around pile and pore water pressure[J]. Chinese Journal of Rock Mechanics and Engineering，2004，23(1)：153–158.(in Chinese))
[22] 雷华阳，李 肖 ，陆培毅，等. 管桩挤土效应的现场试验和数值模拟[J]. 岩土力学，2012，33(4)：1 006–1 012.(LEI Huayang，LI Xiao，LU Peiyi，et al. Field test and numerical simulation of squeezing effect of pipe pile[J]. Rock and Soil Mechanics，2012，33(4)：1 006–1 012.(in Chinese))
[23] 徐永福，傅德明. 结构性软土中打桩引起的超孔隙水压力[J]. 岩土力学，2000，21(1)：53–55.(XU Yongfu，FU Deming. Excess pore pressure induced in piling in saturated structural soft soils[J]. Rock and Soil Mechanics，2000，21(1)：53–55.(in Chinese))
[24] 侯荣彬. 考虑初始损伤效应的软岩巷道围岩时效变形损伤机制及控制对策研究[博士学位论文][D]. 徐州：中国矿业大学，2018.(HOU Rongbin. Effects of Initial damage on time-dependent behavior of soft rock roadway and control countermeasure[Ph. D. Thesis][D]. Xuzhou：China University of Mining and Technology，2018.(in Chinese))
[25] 许宝田，钱七虎，阎长虹，等. 泥岩损伤特性试验研究[J]. 工程地质学报，2010，18(4)：534–537.(XU Baotian，QIAN Qihu，YAN Changhong，et al. Riaxial testing study on damage characteristics of mud stone[J]. Journal of Engineering Geology，2010，18(4)：534–537.(in Chinese))
[26] 王其虎，叶义成，刘艳章，等. 考虑初始损伤和蠕变损伤的岩石蠕变全过程本构模型[J]. 岩土力学，2016，37(增1)：57–62.(WANG Qihu，YE Yicheng，LIU Yanzhang，et al. A creep constitutive model of rock considering initial damage and creep damage[J]. Rock and Soil Mechanics，2016，37(Supp.1)：57–62.(in Chinese))
[27] 柳 飞. 模型试验中地基材料粒径与基础尺寸效应研究[博士学位论文][D]. 青岛：中国海洋大学，2010.(LIU Fei. Study on the particle size effect and scale effect in model test[Ph. D. Thesis][D]. Qingdao：Ocean University of China，2010.(in Chinese))
[28] 姜忻良，徐炳伟，李 竹. 土–桩–结构振动台模型试验相似理论及其实施[J]. 振动工程学报，2010，23(2)：225–229.(JIANG Xinliang，XU Bingwei，LI Zhu. Similitude laws and its application in shaking table test of soil-pile-structure interaction system[J]. Journal of Vibration Engineering，2010，23(2)：225–229.(in Chinese))
[29] 刘红彪，李宏男. 地震模拟振动台试验模型相似设计中的材料弹性模量取值问题研究[J]. 振动与冲击，2016，35(3)：114–120.(LIU Hongbiao，LI Hongnan. Evaluation method for material elastic modulus in the similitude design of structural shaking table test[J]. Journal of Vibration and Shock，2016，35(3)：114–120.(in Chinese))
[30] 李志刚，徐光黎，袁 杰，等. 针贯入仪在软岩强度测试中的应用[J]. 岩土力学，2016，37(增1)：651–658.(LI Zhigang，XU Guangli，YUAN Jie，et al. Application of needle penetrometer to soft rock strength test[J]. Rock and Soil Mechanics，2016，37(Supp.1)：651–658.(in Chinese))
[31] 张国锋，刘志双，陈显坤，等. 点荷载法测试易风化泥质岩强度的可靠性分析[J]. 岩土力学，2014，35(增1)：292–298.(ZHANG Guofeng，LIU Zhishuang，CHEN Xiankun，et al. Reliability analysis of measuring strongly weathered grey mudstone strength with point load measurement[J]. Rock and Soil Mechanics，2014，35(Supp.1)：292–298.(in Chinese))
[32] 宋喜芳，李建平，胡希远. 模型选择信息量准则AIC及其在方差分析中的应用[J]. 西北农林科技大学学报：自然科学版，2009，37(2)：88–92.(SONG Xifang，LI Jianping，HU Xiyuan. Model selection criterion AIC and its application in ANOVA[J]. Journal of Northwest A&F University：Natural Science，2009，37(2)：88–92.(in Chinese))
2023, Vol. 42 
