Effect of burial depth of a new tunnel on the seismic response of an existing tunnel

Burial depth is a crucial factor affecting the forces and deformation of tunnels during earthquakes.One key issue is a lack of understanding of the effect of a change in the buried depth of a single-side tunnel on the seismic response of a double-tunnel system.In this study,shaking table tests were designed and performed based on a tunnel under construction in Dalian,China.Numerical models were established using the equivalent linear method combined with ABAQUS finite element software to analyze the seismic response of the interacting system.The results showed that the amplification coefficient of the soil acceleration did not change evidently with the burial depth of the new tunnel but decreased as the seismic amplitude increased.In addition,the existing tunnel acceleration,earth pressure,and internal force were hardly affected by the change in the burial depth;for the new tunnel,the acceleration and internal force decreased as the burial depth increased,while the earth pressure increased.This shows that the earth pressure distribution in a double-tunnel system is relatively complex and mainly concentrated on the arch spandrel and arch springing of the relative area.Overall,when the horizontal clearance between the center of the two tunnels was more than twice the sum of the radius of the outer edges of the two tunnels,the change in the burial depth of the new tunnel had little effect on the existing one,and the tunnel structure was deemed safe.These results provide a preliminary understanding and reference for the seismic performance of a double-tunnel system.

Influences of burial process on diagenesis and high-quality reservoir development of deep-ultra-deep clastic rocks:A case study of Lower Cretaceous Qingshuihe Formation in southern margin of Junggar Basin,NW China

Taking the Lower Cretaceous Qingshuihe Formation in the southern margin of Junggar Basin as an example,the influences of the burial process in a foreland basin on the diagenesis and the development of high-quality reservoirs of deep and ultra-deep clastic rocks were investigated using thin section,scanning electron microscope,electron probe,stable isotopic composition and fluid inclusion data.The Qingshuihe Formation went through four burial stages of slow shallow burial,tectonic uplift,progressive deep burial and rapid deep burial successively.The stages of slow shallow burial and tectonic uplift not only can alleviate the mechanical compaction of grains,but also can maintain an open diagenetic system in the reservoirs for a long time,which promotes the dissolution of soluble components by meteoric freshwater and inhibits the precipitation of dissolution products in the reservoirs.The late rapid deep burial process contributed to the development of fluid overpressure,which effectively inhibits the destruction of primary pores by compaction and cementation.The fluid overpressure promotes the development of microfractures in the reservoir,which enhances the dissolution effect of organic acids.Based on the quantitative reconstruction of porosity evolution history,it is found that the long-term slow shallow burial and tectonic uplift processes make the greatest contribution to the development of deep-ultra-deep high-quality clastic rock reservoirs,followed by the late rapid deep burial process,and the progressive deep burial process has little contribution.

Effects of Sand Burial on the Survival, Growth, and Biomass Allocation in Semi-shrub Hedysarum laeve Seedlings

Hedysarum laeve Maxim. (Leguminosae) is one of the major species used frequently in revegetation of dune_field in the sandlands of the northern part of China by means of aerial sowing. Seedlings of the species after emergence above the sand surface may be buried in sand to various depths during its establishment in late spring and early summer. A study was made to examine the effects of sand burial at different levels of 0 (control), 33%, 67%, 100% and 133% of their shoot height, on the survivorship, growth, and biomass allocation pattern of H. laeve seedlings (one and two weeks old after emergence). When burial depth was up to 100% of their shoot height, about 70% seedlings died; and the burial at depth of 133% of their shoot height led to death of all seedlings. When seedlings was buried at depth of 33% and 67% of their shoot height, respectively, after six_week growth, their biomass of whole plant, blade, and root and relative growth rate were higher than the unburied counterparts. The seedlings in both 33% and 67% sand burial treatments did not significantly change their biomass allocation pattern comparing with the unburied ones. Furthermore, the number of leaves and shoot height of the seedlings in both 33% and 67% sand burial treatments were not significantly different from those of unburied individuals, respectively. The newly born leaves of the surviving seedlings, in 33%, 67%, and 100% burial treatments, during the period of experiment, were significantly more than those in control.

可降解塑料包装袋土埋降解性能研究

目的塑料污染已成为全球环境污染的一个突出问题,对新型绿色生物可降解塑料的需求不断增加。为评估不同生物可降解材料在土壤环境中的降解性能,并探讨加速材料降解的主要因素。方法设计一系列土埋实验,模拟材料在自然环境中的土壤条件。实验使用淀粉+聚乙烯(PE)、聚乳酸(PLA)+聚己二酸-对苯二甲酸丁二酯(PBAT)+淀粉、聚对苯二甲酸丁二酯(PBT)+聚乳酸(PLA)+玉米基材以及高密度聚乙烯(HDPE)+细胞外基质(ECM)降解母料,并以聚乙烯(PE)作为对照组。通过改变埋土深度、土壤湿度和土壤pH值等实验条件,结合傅里叶红外光谱(FT-IR)、扫描电子显微镜(SEM)、热力学分析等技术,探究不同材料的降解速率、降解性能差异以及材料分子结构可能的变化。结果研究表明,样品的结晶度显著影响其降解性能。尤其是PLA+PBAT+淀粉样品,由于分子间作用力增强和热触发运动性能的降低,在实验中表现出较低的最大失重速率和较高的失重峰温,表现出最高的热稳定性和最佳的降解性能。结论样品表现出良好的热稳定性和降解性,为生物可降解塑料的开发和应用提供了科学依据,有助于解决塑料污染问题。

热盆环境对页岩油快速成熟演化的影响——以松辽盆地齐家古龙凹陷为例

松辽盆地上白垩统青山口组和嫩江组地层中发育大量优质页岩,其内部页岩油预测储量巨大,被称为“古龙页岩油”,其中齐家古龙凹陷青山口组地层是松辽盆地页岩油勘探重点.温度是页岩成熟演化最重要的因素,然而,松辽盆地的热盆环境对页岩油成熟的影响程度尚不清楚.为了理清松辽盆地齐家古龙凹陷古地温场演化特征及其对古龙页岩成熟过程的影响,本文以镜质体反射率(Ro)作为约束条件,利用盆地模拟软件和Easy%Ro动力学模型恢复了研究区多口钻井的埋藏史-热史-生烃史,进而揭示了页岩热成熟演化过程.热史模拟结果揭示齐家古龙凹陷青山口组地层自沉积后地层温度快速升高,在明水组末期(约65 Ma)达到最大古地温,之后受地层抬升作用影响而逐渐冷却.生烃史模拟结果揭示出齐家古龙凹陷青山口组页岩在嫩江组时期(83~72 Ma)进入生烃门限,在约55 Ma时成熟度达到最大.其中,齐家古龙凹陷中部达到高成熟阶段,而凹陷南部和北部分别进入中-高成熟和中-低成熟阶段.古地温场控制着页岩热成熟度演化开始时间和最终状态.松辽盆地青山口组页岩生烃过程可划分为两个阶段:从嫩江组末期至明水组末期的高古地温梯度造成页岩快速深埋增温,页岩快速成熟生油;嫩江组末期之后,地层保持在一定较高温度范围内,页岩热成熟度缓慢增加.齐家古龙凹陷青山口组地层受古地温梯度高和古埋深大的影响,页岩热演化程度最高,成为松辽盆地最重要的页岩油勘探与开发区.和国内外其他盆地相比,松辽盆地热盆环境对齐家古龙凹陷页岩油快速成熟演化具有重要的催化促进作用.本研究成果可为古龙页岩油成藏研究和勘探开发提供理论依据.

从乡村集镇到制表城市:犹太移民社区在拉绍德封的形态发展研究

在18-20世纪工业革命与现代城市建设浪潮下,犹太移民进入钟表制作之城拉绍德封,构筑了以集体记忆为核心的犹太移民社区。本文结合移民历史研究,基于城市空间形态与建筑类型分析梳理移民社区的形成历程、组成要素和组织机制,总结移民社区在城市发展中的角色及其空间变化特点,为理解移民社区的空间营造及建筑演进提供新的思考方向,进一步推动历史社区的遗产保护和文化传承。

拓跋鲜卑勋贵归葬制度的演变与北魏民族交融

在墓志铭和历史文献中,多有拓跋鲜卑勋贵归葬的记载。北魏建国后,道武帝定都平城,并规划了京畿,由于在平城京畿内、外还有拓跋鲜卑人部落组织的残存,因此这对拓跋鲜卑勋贵的归葬产生很大影响。北魏前期,国家使一些鲜卑勋贵可以陪葬金陵,这种陪葬是优恤拓跋鲜卑贵勋的特殊归葬。而对大多数拓跋鲜卑勋贵而言,他们亡故后,一般都归葬于族人墓地,因而,代北地区成为他们主要的安葬地。孝文帝迁都洛阳后,改革了迁洛拓跋鲜卑勋贵的归葬规定,使这些勋贵都以洛阳为籍贯,并确定他们的归葬地与籍贯紧密结合。这些规定割断了拓跋鲜卑勋贵与代北族人墓地的联系,并促使他们效法汉族世家大族的归葬。孝文帝还将迁洛拓跋鲜卑勋贵的归葬划分等次,分别陪葬长陵、景陵及归葬家族墓地。拓跋鲜卑勋贵归葬出现的等次区分及确定归葬地观念的改变,遂成为促进拓跋鲜卑勋贵向汉族世族大族演变的重要环节,并推动了北魏民族交融。

Organic carbon source and burial during the past one hundred years in Jiaozhou Bay,North China

Organic carbon （OC）, total nitrogen （TN）, and ^210Pb in core sediment were measured to quantify the burial of organic carbon and the relative importance of allochthonous and autochthonous contributions during the past one hundred years in Jiaozhou Bay, North China. The core sediment was dated using ^210Pb chronology, which is the most promising method for estimation of sedimentation rate on a time scale of 100-150 years. The variation of the burial flux of organic carbon in the past one hundred years can be divided into the following three stages： （1） relatively steady before 1980s; （2） increasing rapidly from the 1980s to a peak in the 1990s, and （3） decreasing from the 1990s to the present. The change is consistent with the amount of solid waste and sewage emptied into the bay. The OC：TN ratio was used to evaluate the source of organic carbon in the Jiaozhou Bay sediment. In the inner bay and bay mouth, the organic carbon was the main contributor from terrestrial sources, whereas only about half of organic carbon was contributed from terrestrial source in the outer bay. In the inner bay, the terrestrial source of organic carbon showed a steady change with an increase in the range of 69%-77% before 1990 to 93% in 2000, and then decreased from 2000 because of the decrease in the terrestrial input. In the bay mouth, the percentage of organic carbon from land reached the highest value with 94% in 1994. In the outer bay, the sediment source maintained steady for the past one hundred years.

厚煤层大断面回采巷道支护参数优化研究

长壁工作面回采巷道保持“掘-采”全生命周期内的围岩稳定,对于保障工作面高效生产、井下作业人员安全至关重要。杭来湾煤矿302盘区回采巷道为典型的浅埋深、厚煤层、大断面煤巷,为掌握其矿压显现规律,在302盘区选取“三条、两类”回采巷道为研究对象,通过矿压实测、煤岩力学测试、数值模拟及工程实践等方法开展了浅埋厚煤层大断面回采巷道矿压规律研究,对杭来湾煤矿工作面回采巷道支护参数进行了优化设计,在有效保障巷道围岩稳定的同时,实现了高强度、低密度支护,同时提高了掘巷速度,改善了采掘接续关系,促进了矿井实现安全高效生产。

吉宁煤业2107工作面顶覆岩破断及矿压显现规律研究

为了研究吉宁煤业2107工作面顶板破断和矿压显现规律,在吉宁矿2107工作面辅运巷布置3组钻孔,以测定工作面顶板各层位的覆岩下沉量,利用窥视仪观测顶板破断位置,同时记录工作面支架和超前支架的工作阻力值。结果表明:上覆岩层各层位存在超前破断运移现象,超前破断距离为15~20 m;2107工作面上覆岩层垮落带高度范围为16~19 m,顶板破断角大约65°;2107工作面初次来压步距为33 m,初次来压期间压力显著增大,影响面积大,来压期间中间区域支架的平均工作阻力达到11 451 kN/架;周期来压步距为14 m,来压时处于2107工作面中间区域的支架工作阻力较大,支架平均工作阻力达到10 339 kN/架,工作面支架整体上具有较高的利用率以及较强的适应性。

Assessment on Redox Conditions and Organic Burial of Siliciferous Sediments at the Latest Permian Dalong Formation in Shangsi,Sichuan,South China

The redox sensitive elements, molybdenum （Mo） and uranium （U）, in marine sediments from the latest Permian Dalong （大隆） Formation at the Shangsi （上寺） Section, Northeast Sichnan （四川）, South China, were analyzed by inductively coupled plasma mass spectrometry （ICP-MS） to determine their response to a range of redox conditions, and to estimate the organic carbon burial rate. On the basis of the correlation between anthigenic Mo abundance and organic carbon content in modern oceans, the organic carbon burial rates were calculated for the rocks at Dalong Formation, ranging from 0.48-125.83 mmol/（m^2.d）, which shows a larger range than the mineralization rate of organic carbon at the continental margins （1.6-4.23 mmol/（m^2-d））. The Zr-normalized Mo and U abundances show large fluctuations in the entire section. The maxima of Zr-normalized Mo abundance and thus the maxima of the organic carbon burial rates were observed at the interval between the 155th and 156th beds （404-407 m above the base of Middle Permian）. A decrease （the minimum） in U/Mo ratios is present in this interval. It is speculated that the oxygen-limited conditions and ultimately anoxia or euxinia may develop within this depth interval. In contrast, an enhanced enrichment of Zr-normalized U abundance is found, in association with less enrichment in Zr-normalized Mo abundance in the interval from the 151st to 154th beds （395-404 m above the base of Middle Permian）, inferring the dominance of a suboxic/anoxic depositional condition （denitrifying condition）, or without free H2S. The presence of small quantities of dissolved oxygen may have caused the solubilization and loss of Mo from sediments. It is proposed that the multiple cycles of abrupt oxidation and reduction due to the upwelling at this interval lead to the enhanced accumulation of authigenic U, but less enrichment of Mo. A decrease in the contents of U, Mo, and TOC is found above the 157th bed （407 m above the base of Middle Permian）, in association with the enhanced U/Mo ratio, suggesting the overall oxic conditions at the end of the Dalong Formation.

Burial Dissolution of Ordovician Granule Limestone in the Tahe Oilfield of the Tarim Basin,NW China,and Its Geological Significance

With a comprehensive study on the petrology, geology and geochemistry of some Ordovician granule limestone samples in the Tahe Oiifieid of the Tarim Basin, two stages of burial dissolution were put forward as an in-source dissolution and out-source dissolution based on macro-microcosmic petrology and geochemistry features. The main differences in the two stages are in the origin and moving pass of acid fluids. Geochemical evidence indicates that burial dissolution fluids might be ingredients of organic acids, CO2 and H2S associated with organic matter maturation and hydrocarbon decomposition, and the in-source fluid came from organic matter in the granule limestone itself, but the out-source was mainly from other argillaceous carbonate rocks far away. So, the forming of a burial dissolution reservoir resulted from both in-source and the out-source dissolutions. The granule limestone firstly formed unattached pinholes under in-source dissolution in situ, and afterwards suffered wider dissolution with out-source fluids moving along unconformities, seams, faults and associate fissures. The second stage was much more important, and the mineral composition in the stratum and heat convection of the fluid were also important in forming favorable reservoirs.

Neogene Paleoseismic Events and the Shanwang Biota's Burial in the Linqu Area,Shandong Province,China

Several paleoseismic events are recorded in the Neogene Linqu Group, exposed in the Linqu area, Shandong Province, China. The events were interpreted on the basis of fleldwork and laboratory analysis, which showed the presence of seismites with plastically deformed soft-sediment deformation structures in the Shanwang Formation, and of seismic volcanic rocks in the Yaoshan Formation which show brittle deformation. The earthquake-triggered soft-sediment deformations in the seismites include load structures, ball-and-pillow structures, flame structures, piUow-like beds, boudinage structures, slump folds, syn-depositional faults, veins of liquefied sand, and dikes of liquefied sandy lime-mud. The seismic activity is also reflected in what might be called ＇brittle seismites＇; these originated when, under the influence of seismic vibrations, semi-consolidated conglomerate was shattered. Moreover, volcanic activity is related to intense earthquakes that affected basalts intercalated with sand layers; these successions are known as ＇seismic volcanic rocks＇, which are characterized by veins of liquefied sand intruding the basalts. AH above traces of paleoseismic activity were left from one single time span of 4 Ma with active seismicity that took place 14-10 Ma. This time span is known as ＇the Linqu Neogene Paleoseismic Active Period＇, which is divided into four paleoseismic episodes, which were responses to tectonic extension and basin rifting in this area. It even includes the activity of the Yishu Fault Zone during the Miocene and the Neogene. The ratios of trace elements in the seismites, w（La）/w（Sc） and w （La）/w（Th） are higher than the average value of the upper crust, but w（Th）/w（Sc） is lower; this is geochemical evidence for the basin rifting that resulted in a high sedimentation rate. The intense and frequent paleo-earthquakes are held responsible for the rapid burial of the Shanwang Biota. Secondary earthquake-induced processes （e.g. slumping of a lake shore and the strongly increased lacustrine sedimentation rate） contributed to the rapid burial of the biota.

Growth and physiological responses of Agriophyllum squarrosum to sand burial stress

Agriophyllum squarrosum is an annual desert plant widely distributed on mobile and semi-mobile dunes in all the sandy deserts of China. We studied the growth and physiological properties of A. squarrosum seedlings under different sand burial depths in 2010 and 2011 at Horqin Sandy Land, Inner Mongolia to understand the ability and mechanism that A. squarrosum withstands sand burial. The results showed that A. squarrosum had a strong ability to withstand sand burial. Its survival rate, plant height and biomass increased significantly at a burial depth 25% of seedling height and decreased significantly only when the burial depth exceeded the height of the seedlings; some plants still survived even if the burial depth reached 266% of a seedling height. The malondialdehyde （MDA） content and membrane permeability of the plant did not change significantly as long as the burial depth was not greater than the seedling height; lipid peroxidation increased and cell membranes were damaged if the burial depth was increased further. When subjected to sand burial stress, superoxide dismutase （SOD） and peroxidase （POD） activities and free proline content increased in the seedlings, while the catalase （CAT） activity and soluble sugar content decreased. Sand burial did not lead to water stress. Reductions in photosynthetic area and cell membrane damage caused by sand burial may be the major mechanisms increasing mortality and inhibiting growth of the seedling. But the increases in SOD and POD activities and proline content must play a certain role in reducing sand burial damage.

Using seismic surveys to investigate sediment distribution and to estimate burial fluxes of OC, N, and P in a canyon reservoir

As a high-precision survey method,seismic surveying has been increasingly applied to inland water research,although its application to artificial reservoirs has remained limited.As a special artificial water body,reservoirs have important effects on the fluvial transport of material from land to ocean,and inevitably have complex terrain which can complicate and distort the results of seismic surveys.Therefore,there are still some problems need to be resolved in the application of seismic surveys in reservoirs with complex terrain.For this study,the Dongfeng Reservoir located in the upper reaches of the Wujiang River was chosen as an example to test the seismic survey method.Our testing showed that(1)because of the complex underwater terrain,the signal-to-noise ratio of the echo signal in canyon reservoir is low,making it difficult to determine sediment layers thicknesses in some areas;and(2)due to the large spatial heterogeneity of sediment distribution,insufficient density of cross-sections can lead to inaccurate interpolation results.To improve the accuracy of calculations,a mathematical method was used.Ultimately,the total burial mass of sediment was estimated at 2.85 x 107 tons,and the average burial rates of total organic carbon,total phosphorus,and total nitrogen were estimated at 0.194,0.011,and 0.014 g cm-2 year-1,respectively.These values were close to the results of previous studies and hydrographic station data,indicating that seismic survey can be a reliable and efficient method for the mapping of reservoirs.

Effect of tillage and burial depth and density of seed on viability and seedling emergence of weedy rice

Weedy rice(Oryza sativa f. spontanea) is one of the three worst paddy weeds in most rice growing areas. The unexpected heavy infestation is derived from a persistence of soil seed bank of weedy rice, which the shattered seeds chiefly feed back to. Information on soil seed bank dynamics is imperative to predict the infestation of weeds. In the present paper,the effect of rotary tillage on weedy rice seed bank structure was studied first, and a burial experiment of marked seeds was conducted to observe the overwintering survival, seed viability and seedling emergence of weedy rice. The results showed that the proportion of weedy rice seeds in deeper soil increased but seedling emergence decreased with increasing plowing depth. The viability of weedy rice seeds decreased as the burial duration time extended but more slowly in deeper soil layers. Additionally, there was no significant effect of burial density on seed viability. Moreover, the logistic model fitted well(R^2≥0.95, P≤0.01) with the depressive trends of seed viability with increasing burial time under all burial depths and densities which can provide us further information about seed survival. In field experiments, number of seedling emergence significantly decreased as seed burial depth increased, conversely, proportion of seedling emergence increased as seed burial density decreased. This study has important implications for determining strategies for weedy rice management by exhausting its seed bank through the alteration of tillage practices.

大断面浅埋暗挖隧道双侧壁导坑法临时支撑拆除施工技术

随着城市地下工程的不断发展进步,各种用途的隧道不断修建,隧道施工技术水平也不断提高与发展。这也使城市地铁的建设更加复杂,相较于传统以明挖法为主的施工方式,目前地铁隧道施工普遍会将明挖、盖挖、浅埋暗挖等多种方式结合进行施工,极大地推动了城市地下轨道交通工程的快速发展。实践证明,选择一种合理的施工方法是城市地下轨道交通工程成败的关键。西安市地铁14号线机场站站后配线浅埋暗挖隧道采用“双侧壁导坑法”进行施工,本文简要介绍了双侧壁导坑法临时支撑拆除的施工工艺,并以首段18m的监测数据作为依据,总结经验,指导施工。

裸岩浅埋无封底PC组合围堰设计与施工关键技术

潍宿高铁墙夼水库特大桥53#~55#水中墩承台基础为挖井基础,墩位处最大水深为6.6 m,围堰内河床岩层为砂岩,基本无覆盖层。54#墩的承台施工采用钢管桩与钢板桩组合围堰,针对裸岩浅埋无封底围堰的施工特点,通过建模分析各个工况下围堰体系的变形与受力情况,表明围堰结构及整体稳定性安全。无封底钢管桩与钢板桩组合围堰的综合性施工难度较大,介绍铣槽、沉桩、基槽内清淤、柱脚锚固浇筑等关键施工技术,现场实施效果良好。

Burial fluxes and sources of organic carbon in sediments of the central Yellow Sea mud area over the past 200 years

Long-term changes of composition, sources and burial fluxes of TOC （total organic carbon） in sediments of the central Yellow Sea mud area and their possible affecting factors are discussed in this paper. Firstly, similarity analysis is employed to confirm that the carbon burial features resulted from two collected cores are typical in the central Yellow Sea mud area where YSWC （Yellow Sea Warm Current） is prevalent. On this basis, the burial flux of TOC here was considered to be 235.5-488.4 pmol/（cm^2.a） since the first industrial revolution, accounting for about 70%-90% among burial fluxes of TC （total carbon） in the sediments. Compared TOC/TC ratio in the two cores with that in other marine sediments worldwide, we suggest that the growth of calcareous/non-calcareous organisms and dissolution of IC （inorganic carbon） are important factors controlling the TOC/TC ratio in sediment. Results of two-end mixed model based on fi13C data indicate that marine-derived organic carbon （OCa） is the main part among total burial organic carbon which accounts for a ratio over 85%. Due to the high TOC/TC ratio in the two cores, TC in the sediments also mainly exists as OCa, and the proportion of OCa is about 60%-80%. Away from the shore and relatively high primary production in upper waters are the main reasons that OCa is predominant among all burial OC in sediments of the central Yellow Sea mud area. Burial of OC in this mud area is probably mainly influenced by the human activities. Although the economic development during the late 19th century caused by the first industrial revolution in China did not obviously increase the TOC burial fluxes in the sediments, the rise of industry and agriculture after the founding of new China has clearly increased the TOC burial flux since 1950s. Otherwise, we also realize that among TC burial fluxes, TIC account for about 10%-30% in sediments of the central Yellow Sea mud area, so its burial could not be simply ignored here. Distinct from TOC burial, long-term TIC burial fluxes variations relate with climate changes more closely： the East Asian summer monsoon may influence the strength of the Huanghe River （Yellow River） flood, which could further affect the transport of terrestrial IC from land to the central Yellow Sea as well as the burial of these IC in the sediments.

Improving the Treatment of the Vertical Snow Burial Fraction over Short Vegetation in the NCAR CLM3

One deficiency of the NCAR Community Land Model （CLM3） is the disappearance of the simulated snow even in the middle of winter over a boreal grassland site due to unrealistically modeled high downward turbulent fluxes. This is caused by the inappropriate treatment of the vertical snow burial fraction for short vegetation. A new snow burial fraction formulation for short vegetation is then proposed and validated using in situ observations. This modification in the CLM3 largely removes the unrealistic surface turbulent fluxes, leading to a more reasonable snowmelt process, and improves the snow water equivalent （SWE） simulation. Moreover, global offline simulations show that the proposed formulation decreases sensible and latent heat fluxes as well as the ground temperature during the snowmelt season over short vegetation dominant regions. Correspondingly, the SWE is enhanced, leading to the increase in snowmelt-induced runoff during the same period. Furthermore, sensitivity tests indicate that these improvements are insensitive to the exact functional form or parameter values in the proposed formulation.