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1.
为了研究和评价降雨对滑坡活动的影响过程及其作用,利用地表伸缩计、三维地表位移观测计以及地下水流量和地下侵蚀观测计等现场监测仪器,对一典型的日本结晶片岩滑坡--善德滑坡内部的地下侵蚀特征以及地下侵蚀与该滑坡活动之间的关系进行了定量的分析和研究。研究结果表明,季节性集中强降雨是导致地下侵蚀发生的主要原因。善德滑坡地下侵蚀主要有连续土砂排泄和集中土砂排泄2种侵蚀类型,而结晶片岩滑坡的异常活动主要与暴雨引起的集中土砂排泄型地下侵蚀作用有关。通过对地下侵蚀和滑坡活动之间关系的分析发现,地下侵蚀对善德滑坡不同滑体活动的影响作用表现出不同的特征。其中,厚度为10~20 m的浅层滑体,地下侵蚀的影响作用最为显著,而对于具有深层滑动面的滑体(>20 m)其影响作用并不明显。  相似文献   

2.
The mechanism of creep movement of the Zentoku landslide in crystalline schist has not been studied in detail because of the steepness of the slope, very slow movement, low population density and complex topographic and geologic characteristics. Sassa et al. (1980: Proc. INTERPRAEVENT 1, 85–106) and Sassa (1984: Proc. 4th International Symp. on Landslides, Toronto, vol. 2, pp. 179–184; 1985. Geotechnical classification of landslides, Proc. 4th International Conference and Field Workshop on Landslides, Tokyo, pp. 31–40; 1989: Landslide News, Japan Landslide Society, No. 3, pp. 21–24) monitored landslide movement and groundwater level at the Zentoku landslide on Shikoku Island, southwestern Japan, and suggested that the mechanism may be caused by underground erosion. To study the influence of underground erosion at this site, continual monitoring of suspended sediment and water discharge from a groundwater outlet (i.e. a spring) was implemented. The locations of groundwater flow paths were determined, as were the amounts of discharged sediment. Slope deformation was monitored by means of a borehole inclinometer. The conclusions were as follows: (1) the flow paths were found to be on or above the shear zones in which underground erosion has occurred; (2) in addition to being a result of precipitation and groundwater discharge, sediment discharge is affected by landslide activity; and (3) the mechanism of creep movement is an interrelated chain process that combines underground erosion caused by landslide activity with landslide activity caused by underground erosion. Thus, landslide activity increases erosion susceptibility and transportation of soils within the mass, and underground erosion causes instability of the landslide mass, in turn.

This mechanism can explain the observed phenomenon that the Zentoku landslide not only moves actively during heavy rain, but also continues to creep throughout the year.  相似文献   


3.
On Shikoku Island, which is one of the four main islands of Japan, a large number of large-scale crystalline schist landslides have been revealed and are being monitored by an observation system. Seasonal heavy rainfall is the most active meteorological factor that can threaten the stability of this kind of site-specific landslide. In this paper, on the basis of the study of the rainfall-related behavior of a typical crystalline schist landslide, the Zentoku landslide, by analyzing the precisely and continuously observed piezometric and movement data, a method was developed to quantitatively assess the effect of heavy rainfall on a large-scale landslide. The results indicated that heavy rainfall-induced landslide displacement shows good correlation with the variation of groundwater levels. Variations of groundwater level have been simulated with the use of a tank model. The simulation using this model permits the change in water levels for future rainfall events to be predicted. By combining the predicted results with the empirical relation between displacements and water levels, rainfall-induced landslide movement during extreme rainfall events can be estimated in advance. The effect of heavy rainfall on sliding behavior can be quantified in terms of the change in displacement. Thus warning information or advisories for the local residents can be provided.  相似文献   

4.
Guo-Quan Wang 《Landslides》2012,9(1):117-130
Global positioning system (GPS) technologies have been increasingly employed to monitor landslide movements. This paper demonstrates the use of GPS in the study of a creeping landslide in Ponce, Puerto Rico. The landslide is primarily composed of chalk colluvium that extends to depths of about 30 m at the head zone and 2 to 3 m at the toe zone. The slip surface lies at the base of the chalk colluvium, which slides southeast over a weathered brown mudstone unit. GPS monitoring of the landslide began in March 2008. Both campaign rapid static and continuous static GPS surveying methods were applied. Precision at the level of 0.5 mm horizontally and 1.3 mm vertically was achieved through 24-h continuous GPS monitoring. Rainfall data from a local weather station was also integrated into the study. Rainfall heavily influenced the movements of the landslide. A heavy rainfall in September 2008, which dumped 50 cm rain on the landslide area over a 4-day period, temporarily accelerated the sliding and generated rapid movement of 1 m horizontally and 0.5 m vertically. The slide slowed markedly after this significant movement. A prolonged moderate rainfall in November 2009 also temporarily accelerated the sliding. The landslide remains active. The creeping appears likely to continue in the future with short bursts of rainfall-induced rapid movements. Potential landslide causes are investigated, and two measures to minimize future risk are proposed at the end of the article.  相似文献   

5.
Hou  Runing  Chen  Ningsheng  Hu  Guisheng  Han  Zheng  Liu  Enlong 《Landslides》2022,19(2):437-449

Landslides following rainfall occurrence are a widespread phenomenon. The neglect of this phenomenon leads to serious loss of life when disasters occur. At 03:45 (GMT?+?8) on August 21, 2020, a semi-diagenetic landslide occurred in Zhonghai Village, Hanyuan County, China, which occurred 42 h after earlier rainfall. Nine people privately returned to their homes after evacuation of the dangerous area. In this disaster, eight people were lost and one injured. This study explores the failure characteristics, inducement, and mechanisms of the landslide via field investigations, resident interviews, multi-temporal images, field drilling, and geotechnical tests. Hydrological numerical calculations were also performed to uncover the seepage and transfer processes of the groundwater in the slope. Finally, problems in the current community early warning system were analyzed and corresponding suggestions put forward. The results show that the maximum sliding depth of the landslide was 27.5 m, the total area was 80,000 m2, and the sliding volume was about 58,0000 m3, making it a medium-sized deep landslide. In addition to the vertical seepage of rainfall in the landslide area, the downward movement of rainfall in the back and upper catchment areas along the silt sand strata also affected the stability of the landslide. More needs to be done to make the population aware of this lag phenomenon to achieve scientific disaster reduction. This study not only provides a case study of a lagging semi-diagenetic landslide, but also provides insight into hydrological boundary determination and landslide early warning system construction.

  相似文献   

6.
Kita-Uebaru natural rock slope failure and its back analysis   总被引:3,自引:2,他引:1  
A large landslide occurred in Kita-Uebaru (or Asato) area of Nakagusuku village in Okinawa Island (Japan) on 10 June 2006 after a rainy period of about 9 days. The total rainfall was 126 mm from June 8 till the time of the landslide this period. This landslide destroyed several buildings and roads, and the total travel distance of the landslide was about 110 m. In this article, the authors were concerned with the initiation conditions of Kita-Uebaru landslide and post-failure motions of the landslide body. The observations made in the landslide area, structural geology analyses and outcomes of geotechnical investigations are described first. Then, possible causes of the landslide are investigated through back analyses using as inputs the geological structure and the strength properties of planes of discontinuities involved in the sliding processes. The final part of the article is concerned with the simulation of post-failure motions of the landslide body. The results of the investigations and back analyses indicate that the failure plane was bi-planar and the heavy torrential rainy period for about 3 days was the main cause of initiation of the landslide. The mechanical model presented in this article was capable of capturing the overall features of the landslide body following the initiation of the failure.  相似文献   

7.
Since the impoundment of the Three Gorges Reservoir in June 2003, a number of new landslides have occurred and existing landslides have been made worse. The 1,260 × 104 m3 Baishuihe landslide, located at 56 km west of the Three Gorges Dam, began to deform more noticeably after the first impoundment in early July 2003. The sliding of the two blocks comprising the landslide, one an active block and the other a relatively stable block, became apparent after approximately 5 years of monitoring. Field recordings show that the landslide displacement is affected by the combined effects of the rainfall and water level in the reservoir. These effects have been investigated in the present paper, including the deformation characteristics (movement pattern, direction, displacement and velocity) earmarking the temporal evolution of the active block. Based on a practical creep model of a large rock slide, alert velocity thresholds for pre-alert, alert and emergency phases have been computed corresponding to the imminence of failure. The alert velocity thresholds are being proposed to be included as a part of an early-warning system of an emergency plan drawn up to minimize the adverse impact in the event of landslide failure. The emergency plan is intended to be implemented as a risk management tool by the relevant authorities of the Three Gorges Reservoir in the near future.  相似文献   

8.
滑坡堆积体特征及其成因机理是进一步研究滑坡防治及开发利用的基础与前提。位于青藏高原东北缘的黄河上游群科—尖扎盆地内的康杨滑坡属于典型的巨型古滑坡,其堆积体特征及形成机制在该地区具有典型性和代表性,具有较高的学术研究价值。结合工程地质钻孔资料,通过详细的野外调查、粒度分析等方法对康杨滑坡形态特征、形成年代、滑坡体粒度特征及其成因机理进行了研究,主要认识如下:(1)康杨滑坡为晚更新世晚期发生的泥岩滑坡,体积约为12.59×108?m3,为一典型巨型古滑坡,后壁高耸直立;(2)滑坡前缘曾滑移至黄河北岸,堆积体可能堵塞黄河,后被黄河从中部侵蚀切穿,目前在黄河北岸仍存留有古滑坡堆积体;(3)高原抬升和黄河下蚀等作用可能是滑坡发生的背景条件,降水入渗形成软弱滑带和黄河侧蚀作用可能是触发康杨滑坡的主要因素。  相似文献   

9.
The Tochiyama landslide is one of several complex, deep-seated and large-scale landslides occurring in the Hokuriku Province in central Japan. The landslide is about 2 km long and about 500–1100 m wide; it occupies an area of approximately 150 ha and has a maximum depth of 60 m. The slide developed on a dip-slope structure, and is divisible into three layers in ascending order: older landslide debris and avalanche deposits, younger debris-avalanche deposits, and talus. The landslide complex is still active. A triangulation point on the upper part of the landslide shifted downhill by 3.3 m from 1907 to 1983, indicating an average rate of 4.3 cm/y. In 1991, the average rate of movement on the sliding surface was also 4.3 cm/y as measured by an automatic system with inclinometers installed in borehole No. 1–2. The rate measured for borehole No. 1–3, located 380 m upslope from No. 1–2, was over twice that of No. 1–2 for the same period; it has since accelerated to about 19 cm/y. Thus current movements on the basal sliding surface are inhomogeneous; the head of the slide complex is increasing the horizontal granular pressures on the lower part of the slide block.

On the basis of dating of two tephra layers and14C dating of carbonized wood intercalated within the landslide body, two stages of slide movement have been distinguished. The earlier occurred between about 46,000 to 25,000 years ago, and the latter occurred since 1361 A.D. The following sequence of events is inferred. During the middle Pleistocene, intense tectonic movements occurred in the Hokuriku Province, and as a consequence dip-slopes were developed in the Tochiyama landslide area. Low-angle fault planes (possibly representing slump features) and fracture zones then developed within flysch deposits underlying the landslide area, causing a reduction in shear strength. The erosion base level was lowered during the Würm glacial age, and due to severe erosion and incision of stream valleys, the surface slope angle rapidly increased, and toe resistance decreased. This combination of causes led to the development of a deep-seated primary landslide. As a result of an accumulation of younger deposits, regional uplift and further local erosion, stability of parts of the region decreased and led to landslide activity of a second stage. Reactivated and locally accelerating creep movements occur today and may forewarn of a stage of reactivated, hazardous rapid sliding, such as occurred with the adjacent and analogous Maseguchi landslide in 1947.  相似文献   


10.
917灞桥灾难性黄土滑坡形成因素与运动模拟   总被引:1,自引:0,他引:1  
持续性强降雨是诱发黄土滑坡的主要因素。 2011年9月份的持续强降雨达到50a来最大值, 在陕西省关中地区诱发了多处滑坡, 造成交通中断, 带来了严重灾难。尤其9月17日发生于白鹿塬的灞桥滑坡(917灞桥滑坡), 共造成32人伤亡的灾难性滑坡事件。为了揭示滑坡成因和运动过程, 通过对917灞桥滑坡灾害的调查和分析, 揭示了灾害的特点和诱发因素, 通过滑坡运动模拟还原了其运动过程和成灾范围。(1)9.17灞桥滑坡体相对高度大约90m, 宽170m, 滑动厚度约10m; 滑动方向为60, 滑动距离约150m, 总方量约15104m3; 滑坡共发生3次滑动, 滑动方量分别为9.5104m3、3.5104m3和2104m3, 平均堆积厚度12m左右; (2)917灞桥滑坡诱发因素主要是长历时的强降雨、开挖后的高陡边坡和特殊的黄土结构性。充足的前期降雨和当日的强降雨是滑坡发生的主要激发因素; 开挖后形成的高陡边坡发育一系列裂隙, 促使滑坡的发生; 裂隙的产生为降雨的优势渗流提供了通道, 加速了滑坡的发生。(3)利用LS_RAPID对917灞桥滑坡进行模拟, 根据模拟结果, 滑坡可以分为3个阶段, 起动加速滑动阶段(0~7.5s), 沿x方向速度从0迅速增加到4.9ms-1, 沿y方向速度从0迅速增加到8.4ms-1; 滑坡体在这一阶段共滑动了65m; 减速滑动极端, 速度开始降低(7.5~14s), x、y方向的平均速度分别降到1.5ms-1和2.5ms-1, 滑坡在这一阶段向前运动了50m; 堆积停止阶段(15~28.6s), 滑坡运动速度持续降低, 堆积厚度逐渐变薄, 滑坡体共向前滑动了175m, 滑坡最大堆积厚度为14m, 与野外调查结果基本一致。结果对认识和研究此类滑坡成因机理具有重要的借鉴意义, 也可为今后该地区防灾和减灾提供参考。  相似文献   

11.
以东南沿海地区花岗岩残积土为代表性土样,以土体斜坡坡度、降雨强度为控制变量,设计了降雨滑坡模拟试验方案,在大雨、暴雨、大暴雨、特大暴雨等四种不同降雨等级条件下对四种不同坡度的斜坡模型进行了强降雨模拟试验,研究降雨强度和斜坡坡度对其滑塌破坏的影响特征。结果表明:降雨强度越大,发生深层破坏或浅层整体破坏的趋势越明显,其变形跨塌滑块尺寸越大,破坏范围越集中,破坏程度增强;同时土体裂纹出现的时间越早,斜坡滑塌破坏所需的降雨时长逐渐减少。随斜坡坡度的增大,破坏形式由滑落滑坡逐步转化散落崩塌破坏,其相应斜坡滑塌破坏所需的降雨时长减少。研究结论对揭示降雨引发残积土滑坡等地质灾害发生规律具有重要的理论和现实意义。  相似文献   

12.
A large deep-seated landslide, triggered by a heavy rainfall, activated early in the morning on May 19, 2010 along the SW slope of Gírová Mt., NE Czech Republic. The landslide occurred within a zone of pre-existing deep-seated gravitational deformation, and it was accompanied with pronounced ground liquefying in the central and lower portion of the sliding mass. The precipitation that triggered the landslide was about 244.6 mm that fell between May 15th and 18th with an average of 61 mm/day. No properties or lives were lost. However, the landslide provided a good case study on triggering factors and process of liquefaction at mountain slopes in the E Czech Republic and adjacent areas.  相似文献   

13.
舟曲是我国滑坡灾害最严重的地区之一,其中断裂带滑坡活动频繁,危害巨大。文章在综合遥感、变形监测和现场调查的基础上,研究了断裂带滑坡特征及其灾害效应,提出了风险防控对策。研究表明:(1)断裂带滑坡形态上主要为长条形和簸箕形;滑体、滑床一般为板岩、千枚岩碎块石组成,滑带土为含砾黏土;滑坡具有多级、分块活动特征且块体差异性滑动特征显著;滑坡一般为慢速滑动,具有蠕滑特征;滑坡具有降雨敏感性特征,深层滑坡对降雨响应有明显的滞后性。(2)断裂带滑坡的成灾模式主要为慢速滑动过程中的蠕滑拉裂效应和冲击推挤效应,滑动后的堵江淹没效应、挤压侵蚀效应,以及社会影响效应等。(3)断裂带滑坡规模较大,地层破碎,治理条件差,工程治理措施难以奏效。但其突发性不强,应以管防为主,宜采取用地管控、监测预警、避险搬迁等防治措施,慎用工程治理措施。  相似文献   

14.
降雨及库水位联合作用下秭归八字门滑坡稳定性预测   总被引:3,自引:0,他引:3  
张桂荣  程伟 《岩土力学》2011,32(Z1):476-0482
针对三峡库区库水位调控方案和极端降雨情况,对秭归县八字门滑坡稳定性分析设置了10种计算工况,采用SEEP/W软件模拟该滑坡在降雨入渗及库水位联合作用下的暂态渗流场,并利用SLOPE/W软件,将暂态孔隙水压力分布用于该滑坡的极限平衡分析中,确定不同工况下(不同降雨强度)的滑坡稳定性系数,据此采用降雨量对该滑坡进行失稳预测。研究认为:150 mm/d以上的降雨量对该滑坡影响较大,降雨入渗具有滞后性;在相同的降雨量情况下,1 d的降雨强度比5 d的连续降雨对滑坡体的稳定性影响更明显;在水位从175 m降至145 m的过程中,临界雨量为100 mm/d时,滑坡就可能失稳;水位从145 m升至175 m的过程中和175 mm稳定水位时,当临界雨量为200 mm/d时,滑坡才可能失稳,即水位骤降过程中滑坡失稳概率大。不同工况下的滑坡土体含水率分析结果表明,降雨影响的主要是上部土体,下部土体含水率受控于地下水位,即降雨更容易引起浅层滑坡与局部滑坡  相似文献   

15.
南京猪头山滑坡属于典型的覆盖层滑坡,2003年5月边坡发生缓慢变形失稳,没有对周围造成很大的危害,故未引起足够重视,2016年6~7月间受强降雨的影响再次发生大规模的滑动。研究发现,该滑体的地层具有特殊地质结构,在强降雨条件下会产生暂时性承压水,在其承压水的渗透力及浮托力作用下,其稳定性将会大大下降,因此该滑坡的再滑动与降雨密切相关。本文运用数值模拟方法分析了滑坡变形过程与降雨时长及降雨强度之间的关系,结果表明猪头山山前缓坡的稳定性随降雨时长和降雨强度增大逐渐降低,且具有一定的突变性,其滑坡面的位置位于坡体填土层的下部,较好地揭示了猪头山降雨型滑坡形成的机理以及滑坡再滑动机制。这一研究为所在地区的降雨性滑坡预报和治理提供了科学依据。  相似文献   

16.
以陕西省洛南县刘涧滑坡为研究对象,采用颗粒流离散元法对其破坏运动过程进行数值模拟。首先通过双轴数值试验对滑坡饱和土体进行细观参数标定,并与室内试验中饱和土体宏观力学参数进行对比,经验证该细观参数能应用到滑坡的破坏运动分析中,进而引入颗粒流(PFC2D)程序中平行黏结模型,采用ball-wall建模方法建立滑坡模型,对滑坡不同关键部位颗粒进行位移、速度监测,阐明其破坏运动特征。模拟结果表明,降雨为刘涧滑坡的直接诱发因素,斜坡变形破坏模式为由坡脚开挖引起的自前缘向后部牵引-孔隙水压力诱发的后部向前缘推移式滑塌。总体特征为上部推移,中部剪切,下部牵引;滑坡滑动最高时速13.4 m/s,最大滑移170 m,滑动阶段持续25 s。利用颗粒流法对滑坡的破坏运动过程模拟具有较好的适用性,可为工程决策提供依据。   相似文献   

17.
Sun  Shu-wei  Pang  Bo  Hu  Jia-bing  Yang  Zhao-xi  Zhong  Xiao-yu 《Landslides》2021,18(7):2593-2607

Owing to the heavy rainfall, a landslide occurred at the Anqian Iron mine, at 18:00(UTC + 8) on November 24, 2019, in China. The landslide was about 3.0?×?104 m3 and caused damage to the road of transporting waste materials. Failure characteristics and the mechanism of this landslide were analyzed in this study. The landslide area was divided into three parts: the rear tension cracking area, the middle sliding deformation area, and the front colluvium area. A contact-free measuring technique using the new ShapeMetrix3D system was applied and 204 joints were analyzed based on equal-angle stereographic projection. Thus, a conceptual model of the mechanism of the landslide was constructed and the formation process of the landslide was divided into three stages: the first shearing and dislocation stage; the second sliding, front bulging, and rear tractive cracking stage; and the third local rock mass collapse and colluvium depositing stage. Numerical modeling was performed to discover the landslide mechanism by progressively reducing the shear strength of rock mass. The results showed that the original slope was stable, whereas heavy rainfall triggered the landslide, and the predicted failure surface matched closely the field investigations. The factor of safety obtained by real three-dimensional analyses was slightly higher than that obtained by plane problem analyses, and the difference was attributed to the three-dimensional effect of the landslide. This paper also presents the results obtained from the parametric analysis in order to understand the impact of shear strength parameters on the overall stability of the slope.

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18.
In the Indian Himalaya, a 15 km stretch of the North Sikkim Highway that is exceptionally susceptible to landsliding is characterized by fine-grained, low permeability debris material. Lanta Khola is one of the major debris slides in this stretch and is active every year during the monsoons. Although the relationship between rainfall and landsliding in the area is obvious, there is no previous study of precipitation thresholds for landslide initiation. Review of available rainfall and landslide activity data for the area between 1998 and 2006 suggests that sliding cannot be modeled by typical exponential relationships between cumulative rainfall (E) and rainfall duration (D). An alternative rainfall threshold has been proposed that predicts sliding if normalized cumulative rainfall for more than 15 days exceeds 250 mm. It is suggested that when this cumulative rainfall threshold is exceeded, the debris zone in the affected stretch becomes saturated and fails, causing landsliding.  相似文献   

19.
自2008 年三峡库区175 m试验性蓄水以来,受库水波动及强降雨影响,沿江库岸发生多起顺向古滑坡变形灾害。以三峡库区巫山县塔坪H1滑坡为例,结合近十年滑坡调查勘察与变形监测资料,分析了该滑坡蓄水后的变形特征。通过研究分析认为:(1)塔坪H1滑坡为顺层古岩质滑坡,岩体呈碎裂状,岩性主要为三叠系香溪组软硬相间的砂岩、泥页岩,岩层间夹多套软弱夹层,形成了多级滑带控制的滑坡变形。(2)滑坡变形分为3个区域,位移量变形最大的滑坡前缘消落带区域,最大水平位移已达80 cm,其次是处于缓慢变形状态的曲尺场镇前部区域和后部相对稳定的曲尺场镇区域。(3)数值模拟结果显示,库水位周期性波动影响着滑坡前缘涉水区域稳定性变化,短时强降雨沿岩体结构面入渗会加速滑坡中前部区域稳定性快速下降。在水位波动和短时强降雨的共同影响下,塔坪H1滑坡在每年汛期呈现缓慢变形。目前塔坪H1滑坡中前部处于持续变形阶段,亟需开展滑坡防治工程,提高滑坡稳定性,确保场镇安全。  相似文献   

20.
张晗  高杨  李滨  李军  吴伟乐 《地质力学学报》2022,28(6):1104-1114
固液耦合作用是碎屑流向泥石流转化形成复合型滑坡灾害的关键因素,会导致成灾范围和规模放大,是防灾减灾领域研究中的热点和难点问题之一。文中采用自主研发的滑坡后破坏数值模拟平台(LPF3D,Landslides post failure 3D),以2014年9月强降雨诱发的重庆奉节无山坪滑坡为例,探讨了滑坡在水动力作用下远程成灾的动力过程,揭示了固液耦合影响机制。研究结果显示:水动力作用在滑坡运动过程中主要体现为液化和拖曳两种,两种力学作用的增程效应明显,往往使得碎屑流转化为泥石流,导致远程成灾;基于光滑粒子流体动力学(SPH)方法的两相耦合计算模型,考虑流体状态方程、固体黏塑性本构方程和相间作用力的共同影响,基本还原了强降雨条件下重庆奉节无山坪滑坡两相运动过程;数值计算结果显示无山坪滑坡最大运动速度为34 m/s,最大堆积厚度为21.5 m,堆积面积为0.12 km2,最远运动距离为1300 m,模拟结果同实际滑坡的堆积形态基本一致。综上认为,在高位远程滑坡风险调查与预测过程中,需充分考虑强降雨工况下孔隙水压力和固液相间作用,基于LPF...  相似文献   

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