工程科学与技术2025，Vol.57Issue(5)：167-178,12.DOI:10.12454/j.jsuese.202300986
西北干旱区遗址夯土崩解特征与基质吸力关联性研究
Study on the Correlation Between Disintegration Characteristics of Rammed Earth and Matric Suction in the Northwest Arid Area
摘要
Abstract
Objective Soil erosion at earthen sites in northwest China remains one of the primary factors compromising site stability.Simultaneously,soil disintegration and matric suction are considered key indicators influencing the degree of soil‒water interaction.However,for rammed earth exhib-iting temporal and spatial properties,the characteristics of disintegration and the variation in matric suction during the disintegration process re-main unclear.This study investigates the correlation between disintegration behavior and matric suction to identify the fundamental factors influ-encing the disintegration of rammed earth. Methods The fine disintegration process of rammed earth was examined using a custom-built disintegration apparatus.This apparatus primarily consisted of an electronic balance,a data acquisition system,an automatic flow rate controller,a disintegration tank,a sample basket,a support frame,and sensors.The test specimen was an undisturbed cubic soil sample with a side length of approximately 3 cm.First,the sample basket was suspended from the lower interface of the electronic balance.Its position within the disintegration tank was adjusted to the appropriate height,the balance was zeroed,and the specimen was placed horizontally within the basket.Water was then injected into the disintegration tank at a constant rate via the flow control device until the water level exceeded the top surface of the soil,at which point the water injection was stopped.Test phenomena were promptly observed and recorded.Once the data collected by the acquisition system stabilized over a defined pe-riod,data collection was terminated,marking the end of the soil disintegration process.The disintegration process was then categorized into dis-tinct stages based on variations in the disintegration data,and characteristic values for each stage were calculated.The soil‒water characteristic curve(SWCC)was determined using both the pressure plate method and the filter paper method.The pressure plate method employed axis trans-lation technology to measure the low suction range,whereas the filter paper method relied on a calibration curve to assess the high suction range.The filter paper used was No.203 slow‒filter paper with an ash content of 0.01%.Relevant data points were obtained through staged pressure ap-plication and the calibration curve.Then,the complete soil-water characteristic curve was fitted using the Van Genuchten(VG)model. Results and Discussions The results of the refined disintegration process tests demonstrated that rammed earth disintegration exhibited classifi-cation characteristics and distinct spatiotemporal regularity.The disintegration process for the 11 easily disintegrated rammed earth samples con-sisted of a hygroscopic softening stage,a disintegration stage,and a stabilization stage.In contrast,the difficult-to-disintegrate rammed earth dis-played only the hygroscopic softening stage and the stabilization stage.During the disintegration stage,the primary soil behaviors involved break-ing and separation.Simultaneously,spatiotemporal regularity was more pronounced in the easily disintegrated rammed earth.In the hygroscopic softening stage,the hygroscopic rate followed the sequence:extreme arid area>arid area>semi-arid area.During the disintegration stage,the disintegration rate followed the sequence:semi-arid area>extreme arid area>arid area,and Ming Dynasty>Han Dynasty>Qing Dynasty>Tang Dynasty>Song Dynasty.In addition,the VG model was found suitable for characterizing the soil‒water characteristic curve of rammed earth,with a fitting coefficient exceeding 0.99.Only the initial suction values for the two types of rammed earth exhibited distinct classification characteristics,while their spatiotemporal regularity remained insignificant.This outcome resulted from the fact that the calculation of suction in-dices in the SWCC test was independent of the soil disintegration process.Therefore,an index termed the suction-time change rate was proposed,which integrated the disintegration process and suction changes within the same temporal dimension for comprehensive characterization.The re-sults revealed a one-to-one correspondence between the suction‒time change rate and the disintegration characteristics,both in classification and spatiotemporal regularity.In addition,a suction-time change rate of 2 000 kPa/s during the hygroscopic softening stage can serve as a threshold condition for distinguishing the type of disintegration.A strong quantitative relationship was observed,fitting exponential growth functions with correlation coefficients greater than 0.8.Analysis of the gradient changes in matrix potential energy during the disintegration process also indi-cated a specific correlation between these factors.These findings provided theoretical support for subsequent studies on the erosion mechanisms of site gullies.Finally,the spatiotemporal factors influencing rammed earth disintegration were recognized as complex.For the Tang and Song Dynasty sites,the rammed earth was more resistant to disintegration.Whether this was related to the economic development and tamping technol-ogy of the dynasty,or geopolitical and military strategies,or the different structural functions arising from variations in building types,or to the differences in the quantity of aggregates and the spatial arrangement characteristics between particles and pores under the spatiotemporal condi-tions caused by the variation in building materials,these issues required further research and ongoing enhancement of the related archaeological literature and excavation efforts. Conclusions The results revealed a correlation between matrix suction and the disintegration of rammed earth,indicating that the rate of change in suction over time is the decisive factor influencing the degree of disintegration.This conclusion is supported by an analysis of the gradient changes in matrix potential and pressure potential during the disintegration process.These findings provide significant reference value for re-search on the erosion development mechanisms of gullies at the site.关键词
夯土/崩解特征/分类性/时空性/基质吸力/基质势/吸力‒时间变化率Key words
rammed earth/disintegration characteristic/classification/spatiotemporal regularity/matric suction/matrix potential energy/suction-time change rate分类
建筑与水利引用本文复制引用
崔凯,王冠众,裴强强,黄井镜,高晓甜..西北干旱区遗址夯土崩解特征与基质吸力关联性研究[J].工程科学与技术,2025,57(5):167-178,12.基金项目
国家自然科学基金项目(52068050 （）
41562015) （）
国家重点研发计划项目(2023YFF0905900) （2023YFF0905900）
