土遗址因材料强度低、水稳定性差，易受温湿度波动影响，导致开裂、剥蚀等病害，全球约80%大型土遗址面临此类威胁。封闭式遗址博物馆虽隔绝外界环境，但是博物馆内小环境直接作用于土遗址文物，仍会导致土遗址的各类病害。通过对汉阳陵外藏坑遗址现场病害的调查，外藏坑本体主要发育病害为裂隙，在外藏坑发掘过程中裂隙逐渐发育，并在后期的现场保存过程中病害进一步加剧。基于文物预防性保护思想，急需对汉阳陵外藏坑遗址本体裂隙的发育现状和程度有一个明确而清晰的认识，探究裂隙成因，为下一步裂隙病害治理提供科学依据。

本文在外藏坑遗址裂隙病害调查与热湿环境测试结果的基础上，通过土体水分蒸发与干缩开裂试验、数值模拟方法分析了外藏坑的开裂过程与形成机理，主要研究内容与成果如下：

（1）使用三维激光扫描仪建立了外藏坑遗址的三维模型，基于此对外藏坑遗址的裂隙进行了详细的测绘与统计，发现外藏坑地表平面裂隙发育最为严重，平行于坑道长方向的裂隙分布最多，具有长而宽的特点，平行于坑道短方向的裂隙宽度较小，外藏坑立面的竖向裂隙发育严重，多始发于顶部。

（2）对外藏坑遗址的环境温、湿度和本体的温度、含水率进行了周期两年的现场监测，整理监测数据分析了环境温度、湿度与外藏坑遗址本体温度、含水率的变化规律。大气温度表现出明显的季节性特征，温度夏季高冬季低，遗址本体温度与馆内环境温度变化一致，不同外藏坑遗址本体的含水率变化差异显著，遗址本体含水率变化呈现显著的深度分层特征，随着深度的怎加逐渐升高。

（3）分析了不同环境温度、不同试样厚度、不同初始含水率对遗址土体水分蒸发规律与裂隙发育过程的影响，发现：温度越高，初始蒸发速率越大，裂隙越早出现；试样厚度越小失水越快，裂隙发育速度快，裂隙数量增多而宽度小；初始含水率增加，蒸发持续时间长，裂隙总长度增加，分割的土块数量增加。

（4）通过多场耦合软件COMSOL Multiphysics模拟了土块裂隙发育的过程，将模拟结果与试验结果进行对比，验证了计算模型的可靠性。同时模拟了外藏坑在卸荷效应与蒸发作用下的开裂过程，发现裂隙首先在外藏坑夹角处产生，主要沿长方向扩展，表层土体收缩明显。温度的变化会改变外藏坑初始损伤开裂的时间，但裂隙形态无明显差异，初始含水率的不同裂隙发育程度不同，初始含水率与最终裂隙率呈正相关。

Soil sites are characterized by low material strength and poor water stability, making them highly susceptible to fluctuations in temperature and humidity, which in turn lead to a variety of problems such as cracking and erosion. Approximately 80% of large soil sites worldwide are currently facing such threats. Although enclosed site museums can effectively isolate the external environment, the microenvironment within the museum still directly affects the soil site cultural relics, and can still cause various types of damage to the soil sites. Based on the investigation of the on-site damage at the Outer Burial Pits of the Yangling Mausoleum, the main type of damage that has developed in the pits is fissures. These fissures gradually developed during the excavation process of the outer burial pits and further intensified during the subsequent on-site preservation process. In accordance with the concept of preventive conservation of cultural relics, it is urgently necessary to have a clear and accurate understanding of the current status and degree of fissure development in the outer burial pits of the Yangling Mausoleum, to explore the causes of the fissures, and to provide scientific basis for the next steps in the treatment of the fissure damage.

Based on the investigation results of the fissure damage and the testing of the thermo-hygroscopic environment at the Outer Burial Pits site, this paper analyzes the cracking process and formation mechanism of the outer burial pits through soil moisture evaporation and drying shrinkage cracking experiments, as well as numerical simulation methods. The main research contents and achievements are as follows：

(1) A three-dimensional model of the Outer Burial Pits site was established using a 3D laser scanner. Based on this model, a detailed survey and statistical analysis of the fissures at the site were conducted. It was found that the surface of the outer burial pits exhibits the most severe development of planar fissures. The fissures that are parallel to the long axis of the pit are the most numerous and are characterized by their length and width. In contrast, the fissures that are parallel to the short axis of the pit are narrower. The vertical fissures on the side surfaces of the outer burial pits are also severely developed, with many of them originating from the top.

(2) A two-year on-site monitoring campaign was conducted to measure the environmental temperature and humidity, as well as the temperature and moisture content of the outer burial pits themselves. The collected data were processed and analyzed to identify the patterns of variation in environmental temperature and humidity, and the temperature and moisture content of the outer burial pits. The atmospheric temperature exhibited distinct seasonal characteristics, with higher temperatures in summer and lower temperatures in winter. The temperature of the outer burial pits was consistent with the changes in the environmental temperature within the museum. The variation in moisture content of different outer burial pits was significantly different. The moisture content of the outer burial pits showed a pronounced depth-dependent stratification, increasing gradually with depth.

(3) The effects of different environmental temperatures, sample thicknesses, and initial moisture contents on the evaporation patterns of soil moisture and the development of fissures in the site's soil were analyzed. The results showed that higher temperatures led to greater initial evaporation rates and earlier appearance of fissures. Thinner samples lost water more rapidly, with faster fissure development, increased number of fissures, and smaller fissure widths. An increase in initial moisture content resulted in longer evaporation duration, increased total fissure length, and a greater number of soil blocks divided by the fissures.

(4) The cracking process of soil blocks was simulated using the multiphysics coupling software COMSOL Multiphysics. By comparing the simulation results with experimental data, the reliability of the computational model was validated. Additionally, the cracking process of the outer burial pits under the combined effects of unloading and evaporation was simulated. The results revealed that cracks first initiated at the corners of the outer burial pits and predominantly propagated along their longitudinal direction, accompanied by significant contraction of the surface soil layer. While temperature variations altered the initiation time of initial damage-induced cracking in the pits, they exhibited no substantial impact on crack morphology. Conversely, differences in initial moisture content distinctly influenced crack development intensity, demonstrating a positive correlation between initial moisture content and final crack ratio.

[1] 孙满利. 土遗址保护研究现状与进展[J]. 文物保护与考古科学, 2007, (04): 64-70.

[2] 王石斌. 北方土遗址的病害成因与环境区划研究[D]. 兰州大学, 2009.

[3] Environmental control strategies for the in situ preservation of unearthed relics in archaeology museums[J]. Journal of Cultural Heritage, 2015, 16(6): 790-797.

[4] Gu Z L , Luo X , Meng X ,et al.Primitive Environment Control for Preservation of Pit Relics in Archeology Museums of China[J]. Environmental Science & Technology, 2013, 47(3): 1504-1509.

[5] 刘克成. 汉阳陵帝陵外藏坑保护展示厅,西安,陕西,中国[J].世界建筑, 2014(12): 72-75.

[6] 土遗址病害的评估体系研究[J]. 文物保护与考古科学, 2012, 24 (03): 27-32.

[7] Lakshmikantha M R , Prat P C , Ledesma A .An experimental study of cracking mechanisms in drying soils[C]. Proceedings of the 5th International Congress on Environmental Geotechnics. 2006, 533-540.

[8] N,Yesiller,and,et al.Desiccation and cracking behavior of three compacted landfill liner soils[J]. Engineering Geology, 2000, 57 (1-2): 105-121.

[9] Decarlo K F , Shokri N .Effects of substrate on cracking patterns and dynamics in desiccating clay layers[J]. Water Resources Research, 2014, 50(4): 3039-3051.

[10] 王常亚,石玉成,刘琨. 西北干旱、半干旱地区土遗址典型病害及其相关性研究[J]. 地震工程学报, 2023, 45(01): 220-227.

[11] 常彬,李佳轩,李库,等. 超声波雾化技术在汉阳陵土遗址补水保护实验[J]. 西北大学学报(自然科学版), 2025,55(02): 379-388.

[12] 郭青林,裴强强,王彦武,等. 我国土遗址保护研究新进展[J]. 石窟与土遗址保护研究, 2024,3(03): 18-31.

[13] 孙满利,陈彦榕,沈云霞. 土遗址病害研究新进展与展望[J]. 敦煌研究, 2022,(02): 136-148.

[14] 徐方圆,解玉林,吴来明. 文物保存环境中温湿度研究[J]. 文物保护与考古科学, 2009, 21(S1): 69-75.

[15] 杨强义. 环境因素对大明宫丹凤门遗址的影响探究[D]. 西北大学, 2012.

[16] 姚雪,赵凡,孙满利. 汉阳陵帝陵外藏坑遗址温度变化规律及预报模型[J]. 敦煌研究, 2014, (06): 69-74.

[17] 寇天骄. 遗址博物馆环境下土遗址本体水单向蒸发及其影响因素的研究[D]. 西北大学, 2014.

[18] 王觅. 土遗址博物馆的热湿环境研究[D]. 西安建筑科技大学, 2009.

[19] 王觅,闫增峰. 汉阳陵地下博物馆防结露分析研究[C]. 中国建筑学会建筑物理分会. 城市化进程中的建筑与城市物理环境：第十届全国建筑物理学术会议论文集. 西安建筑科技大学建筑学院, 2008:4.

[20] 刘莹. 封闭空间半无限大土体的热湿耦合研究[D]. 西安建筑科技大学, 2011.

[21] 李松璘. 封闭式土遗址博物馆热湿环境 CFD 模拟研究[D]. 西安建筑科技大学, 2011.

[22] 吴士杰. 土遗址博物馆遗址保护厅适宜温湿度参数研究[D]. 西安建筑科技大学, 2013.

[23] 唐朝生,施斌,顾凯. 土中水分的蒸发过程试验研究[J] .工程地质学报, 2011, 19(06): 875-881.

[24] Wilson G W , Fredlund D G , Barbour S L . Coupled soil-atmosphere modelling for soil evaporation[J]. Canadian Geotechnical Journal, 1994, 31(2): 151-161.

[25] Smits K M , Cihan A , Sakaki T , et al. Evaporation from soils under thermal boundary conditions: Experimental and modeling investigation to compare equilibrium‐ and nonequilibrium‐based approaches[J]. Water Resources Research, 2011, 47(5): p.W05540.1-W05540.14.

[26] 杨洋,姚海林,卢正. 蒸发条件下路基对气候变化的响应模型及影响因素分析[J]. 岩土力学, 2009, 30(05): 1209-1214+1220.

[27] 杨松,吴珺华. 粉土表面液滴蒸发特性及对土-水特征曲线的影响[J/OL]. 岩土力学, 2020(S2): 1-9[2020-12-14].

[28] Liu X ,Xu W ,Zhan L , et al.Laboratory and numerical study on an enhanced evaporation process in a loess soil column subjected to heating[J]. Journal of Zhejiang University-SCIENCE A, 2016, 17(7):553-564.

[29] Kayyal M K. Effect of the moisture evaporative stages on the development of shrinkage cracks in soil[C]. In Proceedings of First International Conference on Unsaturated Soils, Paris, 1995: 56-59.

[30] Shokri N, Lehmann P, Vontobel P, et al. Drying front and water content dynamics during evaporation from sand delineated by neutron radiography[J]. John Wiley & Sons, Ltd, 2008, 44(6): 215-224.

[31] 赵士旺. 干湿循环条件下垃圾填埋场毛细阻滞式覆盖层研究[D]. [硕士学位论文]. 哈尔滨: 哈尔滨工业大学, 2014.

[32] 任志胜,解倩,王彤彤,等. 晋陕蒙露天煤矿排土场不同新构土体土壤蒸发特征研究[J]. 土壤, 2016, 48(04): 824-830.

[33] Kondo J， Saigusa N， Sato T. A model and experimental study of evaporation from bare soil surfaces[J]. Journal of Applied Meteorology, 1992, 31(3): 304-312.

[34] Penman H L . Natural Evaporation from Open Water, Bare Soil and Grass[J]. Proceedings of the Royal Society of London, 1948, 193(1032): 120-145.

[35] Wilson G W. Soil evaporation fluxes for geotechnical engineering problems[D]. Saskatoon: University of Saskatoon, 1990.

[36] Monteith J L . Evaporation and Surface Temperature[J]. Quarterly Journal of the Royal Meteorological Society, 1981, 107(451):1-27.

[37] 张华,胡文龙,陈善雄. 一种非饱和土表层蒸发过程的预测方法[J]. 岩土力学, 2014, 35(S2): 129-134.

[38] 林宗泽,唐朝生,曾浩,程青,田本刚,施斌. 基于红外热成像技术的土体水分蒸发过程研究[J]. 岩土工程学报, 2021, 43(04): 743-750.

[39] Thomas H R , Rees S W . The numerical simulation of seasonal soil drying in an unsaturated clay soil[J]. International Journal for Numerical & Analytical Methods in Geomechanics, 1993, 17(2): 119-132.

[40] 陈建斌,孔令伟,赵艳林,吕海波. 非饱和土的蒸发效应与影响因素分析[J]. 岩土力学, 2007(01): 36-40.

[41] Campbell G S. Soil Physics with Basic: Transport Models for Soil-Plant System [M]. Amsterdam: Elsevier, 1985.

[42] G W Wilson , D G Fredlund , and S L Barbour. The effect of soil suction on evaporative fluxes from soil surfaces[J]. Canadian Geotechnical Journal, 1997, 34.

[43] 王铁行,陈晶晶,李彦龙. 非饱和黄土地表蒸发的试验研究[J]. 干旱区研 究, 2014, 31(06): 985-990. 2014.06.01.

[44] 滕继东,单锋,张升,童军. 考虑风速影响的土表蒸发计算方法[J]. 岩土工程学报, 2018, 40(01): 100-107.

[45] 施斌,唐朝生,王宝军,姜洪涛. 粘性土在不同温度下龟裂的发展及其机理讨论[J]. 高校地质学报, 2009, 15 (02): 192-198.

[46] 唐朝生,施斌,顾凯. 土中水分的蒸发过程试验研究[J]. 工程地质学报, 2011, 19 (06): 875-881.

[47] Tang C ,Cui Y ,Shi B , et al.Desiccation and cracking behaviour of clay layer from slurry state under wetting–drying cycles[J]. Geoderma, 2011, 166(1): 111-118.

[48] Liu C ,Tang C ,Shi B , et al.Automatic quantification of crack patterns by image processing[J]. Computers and Geosciences, 2013, 5777-80.

[49] 唐朝生,施斌,刘春等. 影响黏性土表面干缩裂缝结构形态的因素及定量分析[J]. 水利学报, 2007, (10): 1186-1193.

[50] 唐朝生,王德银,施斌等. 土体干缩裂隙网络定量分析[J]. 岩土工程学报, 2013, 35(12): 2298-2305.

[51] 焦少通,王家鼎,张登飞等. 干湿循环作用下黄土厚度对其裂隙发育的影响[J]. 西北大学学报(自然科学版), 2024, 54(01): 1-10.

[52] 胡长明,胡婷婷,朱武卫等. 干湿循环作用下压实黄土裂隙演化特征研究[J/OL]. 长江科学院院报, 2024, 41(03): 1-8.

[53] 姜世新. 土体开裂的理论研究[D]. 天津大学, 2014.

[54] 贾丽娜. 洞穴环境下黄土地层开裂机理试验[D]. 长安大学, 2013.

[55] 龚壁卫,程展林,胡波等. 膨胀土裂隙的工程特性研究[J]. 岩土力学, 2014, 35(07): 1825-1830+1836.

[56] Baer J ,Kent T ,Anderson S .Image analysis and fractal geometry to characterize soil desiccation cracks[J]. Geoderma, 2009, 154(1): 153-163.

[57] KLEPPE J H, OLSON R E. Desiccation cracking of soil barriers[J]. Hydraulic Barriers in soil Rock Astm stp, 1985(874): 13.

[58] 杜长城,祝艳波,苗帅升等.三趾马红土失水收缩裂缝演化规律研究[J]. 岩土力学, 2019, 40(08): 3019-3027+3036.

[59] 叶万军,万强,申艳军等. 干湿循环作用下膨胀土开裂和收缩特性试验研究[J]. 西安科技大学学报, 2016, 36(04):541-547.

[60] 沈珠江,邓刚. 粘土干湿循环中裂缝演变过程的数值模拟[J]. 岩土力学, 2004, (S2): 1-6+12.

[61] Matsubara Hitoshi, Hirose Kosaburo, Edo Taka aki, Tamanaha Kei ichi, Hara Hisao, Yamada Tomonori. Numerical modelling of mudcrack growth[J]. Japanese Geotechnical Society Special Publication, 2016, 2 (31): 1143-1147.

[62] 司马军,蒋明镜,周创兵. 黏性土干缩开裂过程离散元数值模拟[J]. 岩土工程学报, 2013, 35(S2): 286-291.

[63] AMARASIRI A ,KODIKARA J .Numerical modelling of a field desiccation test[J]. Géotechnique, 2013, 63(11): 983-986.

[64] 孙满利,王旭东,李最雄等. 交河故城的裂隙特征研究[J]. 岩土工程学报, 2007, (04): 612-617.

[65] 张景科,谌文武,李最雄等. 交河故城东北佛寺墙体裂隙发育程度反演研究[J]. 敦煌研究, 2007, (05): 59-62+118-119.

[66] 郭志谦,谌文武,张克文等. 中国西北地区气象因子对夯土遗址裂隙发育的影响 [C] 中国地质学会工程地质专业委员会. 2016 年全国工程地质学术年会论文集. 兰州大学西部灾害与环境力学教育部重点实验室土木工程与力学学院; 2016:9.

[67] 秦立科,王琦,段晓彤,等. 汉阳陵K21号外藏坑裂隙调查及稳定性研究[J]. 水文地质工程地质, 2023, 50(06): 137-146.

[68] Chengzeng Y ,Yuchen Z ,Wenhui K , et al.A FDEM 3D moisture migration-fracture model for simulation of soil shrinkage and desiccation cracking[J]. Computers and Geotechnics, 2021, 140.