Analysis of Highway Subgrade Slope Protection and Support Technologies

As an important transportation hub in China,the traffic volume and driving speed are important aspects of expressways.Therefore,the protection requirements for roadbed side slopes are higher,and it is necessary to resist rainwater erosion and other damages by protecting the side slopes.Therefore,it is necessary to adopt effective technical means of subgrade protection and support.This paper mainly summarizes the characteristics of highway subgrade slope protection construction and slope protection and support technologies.

Root structure of slope protection plants in a high-grade highway

Root length and root length density of Lespedeza bicolor,Amorpha fruticosa,and Sea buckthorn were investigated in a country highway-TongSan highway（Tongjiang to Sanya） in Heilongjiang Province,China.The root lengths were divided into five root orders according to Pregizter sequence classification method.Results show that sea buckthorn roots are dominated by coarse roots in the horizontal growth,while L.bicolor has a large proportion of fine roots in vertical conical growth and A.fruticosa is in depth growth.Root length density of L.bicolor in all the root sequences is higher than that of sea buckthorn and A.fruticosa.On the basis of the root structure,it is inferred that L.bicolor roots mainly absorb the surface soil moisture for its normal growth;in contrast,A.fruticosa has good uptake ability to deep soil water.The root structure of sea buckthorn implies that it has a strong drought resistance.

Study on Mechanism and Control Effect of Highway Slope Ecological Protection

At present,with the rapid development of social economy,people's awareness of environmental protection continues to increase,and environmental construction and environmental protection work are put on the agenda.Highway slope greening protection is an important means to achieve social sustainable development.Developed countries carried out research earlier in this area,and China's research in this area started later.In engineering construction,ecological protection is to realize slope reinforcement and slope protection depending on the water storage and soil fixation effects of vegetation.Its slope protection can be summarized as the mechanical effect of root system and the hydrological effect of vegetation.As a basic form of slope greening protection,it is necessary for us to understand the mechanism of ecological protection and to enhance the design of ecological protection accordingly.Based on this,the article analyzed the development of slope greening protection technology and ecological protection mechanism from different angles,so as to establish a theoretical framework for future research.

Study on the Bioengineering Protection Technique for Rock Slopes in Railway

Ecological protection technique of rock slope is a new slope protection technique,and it is used widely in some supporting engineering of rock slope at railway and highway.But it is always an important research in the field of geotechnical engineering, because the study is related to many subjects and is not systemic and idiographic enough.The paper takes the rock slope of Luozhan(from Luoyang to Zhanjiang)

Thermal features of Qinghai-Tibet Railway Embankment with Crushed-stone Slope Protection in Permafrost Regions

The Embankment with Crushed-Stone Slope Protection(ECSSP) in permafrost regions is an effective measure to cool subgrade and protect permafrost.It can mitigate the engineering hazards of the Qinghai-Tibet railway in the permafrost regions. Considering the influence of the noctumal cold air during summer months in Qinghai-Tibet Plateau。

The Application of Three-Dimensional Integrated Protection Technology in High Slope Control of Mountainous Highway

In the process of China's national economy construction,the role of highway traffic is unquestionable.And with the continuous development of society and the continuous improvement of highway grade,the work of the highway slope governance become a top priority,especially for some mountainous area highway,strengthen management of slope is very critical.The emergence of three-dimensional comprehensive protection technology has created great convenience for the management of the slope of the mountainous highway,and the safety of the mountain highway has been improved effectively.In view of this,the paper focuses on the application of three-dimensional integrated protection technology in the treatment of highway high slope in mountainous areas for reference and reference.

Ecological Protection Design Strategy for Mountain Tourism Highway Slopes

Slope ecological protection technology is a form of slope protection with high ornamental and good economic value.At present,it is widely used in highways and urban streets’slope protection works.However,its use is not very common in mountain tourism highways;hence,it is necessary to implement strategies for mountain tourism highway slope ecological protection design to promote excellent development.

Summary of Slope Ecological Protection Technology

It is an important issue for sustainable economic development to give consideration to both project development and environmental protection.At present,we must confront and seriously deal with the problems of rational utilization of resources,protection of the environment and beautification of the environment in engineering construction.This paper describes a variety of slope plant protection technology,which can not only play a good role in slope protection,but also improve the engineering environment and reflect the beauty of natural environment,so as to provide reference for slope ecological protection.

Stability evaluation and protection of slope for Laosongling-Yanji Highway

The authors analyzed the engineering geological characteristics of the slope of the study area (K75+840-K76+340). Two typical cross-sections have been chosen to analyze the failure modes after the excavation of the highway. Different types of the failure modes have been calculated and analyzed. The results show that some dealing methods have been advised to ensure the stability of the slopes.

A Testing Method for Ratio Restraint Characteristics of Differential Relay Protection of Transformers

In this paper, a method to calculate the slope of the ratio restraint characteristic of a transformer differential relay protection is proposed. The method allows using some concise but effective means to get the slope. Modulating the argument of current output from ONLLY testing equipment can make the relay protection device operate, thus, the data used for calculation would be obtained naturally after several trails. In order to make sure how effective that method could be, some experiment data is given as well.

基于地质调查的缓坡地建设适宜性评价——以福建省南平市建阳中心城区为例

为构建缓坡地建设适宜性评价体系,合理划定缓坡地开发适宜区、一般适宜区及禁止建设区,科学开发利用低丘缓坡地资源,以福建省南平市建阳中心城区为研究区,在该区综合地质调查的基础上,以小流域为基本评价单元,以剥蚀阶地代替坡度和起伏度等指标,开展具有城镇建设功能指向的土地资源评价研究。以坡度、土体厚度、坡向-地层产状一致性,以及岩性建造、植被类型等为主要指标,进行地质灾害风险性评价,通过构建生态保护重要性、建设适宜性等多维评价体系,最终集成评价了缓坡地建设的适宜性。结果表明:研究区适宜城镇建设开发的缓坡地资源丰富,主要分布在严墩、新岭、兴田、将口、南林、赤岸、芹口等小流域的一级剥蚀阶地内,发生地质灾害的风险性较小,可以按照组团开发的方式逐步进行开发及利用,研究区属于地质灾害非易发区,但是西岸、水尾等小流域的二级剥蚀阶地、三级剥蚀阶地,土体较厚,坡度较陡,植被主要为杉木和毛竹,如果开发边界规划不合理,容易引发滑坡、崩塌等地质灾害。研究成果对我国低丘缓坡地合理开发利用具有较好的借鉴意义。

三维土工网边坡防护水土保持能力研究

路基边坡防护工程可减轻降雨对坡面土体的侵蚀作用,为深入研究坡面防护材料水土保持能力的定量表征方法,通过室内人工降雨边坡侵蚀模型试验,分析不同降雨强度和不同三维土工网防护下路基边坡的降雨侵蚀规律,提出三维土工网水土保持能力的试验测定方法及相关系数计算公式。研究结果表明:三维土工网防护边坡泥沙流失干质量明显小于相同条件下不设防边坡泥沙流失干质量,土工网防护在减少边坡侵蚀量的同时,有利于边坡侵蚀进程的快速稳定,但土工网的水土保持能力随雨强增大急剧下降。泥沙流失速度随着降雨的持续而逐渐减小,后期趋于收敛稳定,侵蚀历程采用指数函数拟合具有较好的相关性。建议设防边坡的试验降雨时间不少于70 min,不设防的边坡试验降雨时间不小于100 min。水土保持能力系数随雨强的增大呈对数函数关系减小,雨强超过100 mm/h时水土保持能力系数实测值与对数函数拟合值差异较大,建议在测定材料水土保持能力系数时雨强取20~100 mm/h,可取50 mm/h作为标准试验雨强。泡面类三维土工网水土保持能力显著优于普通三维土工网,而双泡面的三维土工网优于单泡面三维土工网。试验条件下凹凸泡面三维土工网的水土保持能力系数主要分布在1.71~3.03,建议50 mm/h雨强三维土工网水土保持能力系数不应小于1.5。

边坡支护工程设计和施工阶段关键技术分析

工程项目在进行建设过程中,不可避免地会出现开挖情况,对于地质较差的地方,为减小开挖工作量,常设置相关边坡防护措施进行及时防护。而边坡的防护形式和措施较多,其应用条件和经济性均不一致,若不进行相关现场分析和评估,盲目采用过大的防护,容易造成经济浪费,因此如何根据设计过程中的数据采用贴合的边坡防护是施工所希望达到的目的。本文以娄底市某边坡工程开挖为例,结合当地场地条件,分别从设计和施工角度对其在项目进行中的关键性技术进行分析,从而提出相关解决方案,达到经济适用性目的。最终结果证明,在施工完成后,该边坡情况良好。拟为相关类似工程提供参考。

土石坝护坡冻胀破坏水-热-力耦合数值模拟研究

针对寒区土石坝护坡普遍存在的冻胀破坏问题,选取寒区某土石坝工程为研究对象,结合土石坝工程特点,建立考虑水-热-力耦合作用的有限元计算模型。研究护坡在库水位和坝体填土水分迁移作用下冻胀破坏全过程,分析土石坝温度场、水分场和位移场的变化规律,并将位移场有限元计算结果与实测冻胀变形资料进行对比,验证有限元计算结果。研究结果表明:冻胀作用对坝坡影响深度约为2 m,坝坡浅层0~2 m范围的温度变化受外界气温影响较大,坝体内部温度相对坝坡浅层变幅小,且有一定的滞后性;负温使坝坡浅层孔隙水相变成冰,宏观上表现为未冻水体积分数的降低,坝坡浅层土石混合体孔隙水相变、坝体填土内水分向坝坡迁移和冻结峰面向坝体内部移动是护坡冻胀破坏的主要因素;大坝坝坡计算冻胀量为20~30 cm,最大值为36 cm,计算结果与实测冻胀变形资料吻合;护坡冻胀破坏主要由砂砾料垫层、坝体填土等土石混合体冻胀及冰推力共同作用引起。研究结果可为寒区土石坝护坡设计提供参考。

裸漏基岩边坡护坡设计与应用

公路工程建设过程中,裸露基岩边坡如不及时采取防护措施极易造成水土流失、滑坡等灾害的发生。结合某三级公路,工程区总体属中低山剥蚀地貌,工程沿线大部分地段基岩裸漏。裸露基岩边坡防护工程的设计与施工,对施工现场高边坡防护、防排水措施等要点进行了论述,通过边坡生态护坡设计,达到施工质量安全双优目标。

典型黑土区坡耕地表层土壤活性有机碳变化特征

以典型黑土区3种地貌类型区(漫川漫岗区、丘陵漫岗区、平原低地区)坡耕地不同坡位表层土壤为研究对象,通过测定土壤总有机碳、高活性有机碳、中活性有机碳和低活性有机碳等指标,分析黑土区坡耕地不同坡位表层土壤活性有机碳的变化特征,探究不同地貌类型区坡耕地土壤活性有机碳变化特征的差异。结果表明,坡耕地各坡位表层土壤总有机碳含量变化范围为26.57~38.61 g/kg,土壤活性有机碳含量变化范围为1.85~5.67 g/kg。3种地貌类型区坡耕地不同坡位土壤总有机碳和活性有机碳含量变化特征不同。漫川漫岗区总有机碳、中活性有机碳和低活性有机碳含量变化特征均表现为坡上和坡中显著大于坡下、坡上和坡中无显著差异;高活性有机碳含量变化特征则以坡中最高坡下最低,且不同坡位之间高活性有机碳含量差异显著。丘陵漫岗区不同坡位土壤总有机碳和低活性有机碳含量差异显著,并表现为坡下显著大于坡上、坡上显著大于坡中;高活性有机碳和中活性有机碳含量的变化则呈现坡上和坡下显著大于坡中、坡上和坡下无显著差异。平原低地区总有机碳及3种活性有机碳组分的含量在各坡位间的差异均为未达显著水平。不同地貌间典型黑土区坡耕地表层土壤活性有机碳分布规律有所差异,漫川漫岗区和丘陵漫岗区坡耕地土壤有机碳活性最差的坡位分别是坡下和坡中,而平原低地区不同坡位间无显著变化。研究结果为黑土坡耕地生态建设与保护技术的针对性设计奠定了理论基础。

坡位对高寒草甸山体断面重建植被及土壤性状的影响

针对川西高寒草甸公路山体断面植被重建的实际技术需求,以G248国道建成3年的护坡草坪植被为样地,通过测定4个坡位(上坡、中坡、下坡和坡底)群落特征、优势种种类、功能群重要值及草坪草性状等植被指标,以及颗粒组成和理化性状等土壤指标,研究坡位对重建植被结构和土壤性状的影响。结果表明:1)低坡位可增加护坡植被的群落密度和投影盖度(P<0.05),但下坡植被基盖度和物种多样性、丰富度、均匀度均最大。2)坡位越低优势种占物种数比例越低,下坡群落高度和第一优势种高度显著低于其他坡位(P<0.05)。3)坡位越低草坪草存活密度、自然高度、分蘖数、生物量和重要值越大(P<0.05),草坪草重要值仅0.04%~16.52%,4个坡位均演替为以乡土植物为主的植被群落。4)坡位显著影响生活型功能群组成(P<0.05),4个坡位中多年生杂类草重要值均为最大,下坡6种生活型功能群组成较为均衡。5)坡位显著影响土壤颗粒组成和理化性状(P<0.05),坡位越高土壤粒级组成越失衡,有机质含量越低且保水供肥能力越差。综上,坡位影响再生植被的群落特征、功能群结构、优势种种类及土壤粒级组成和理化性状,构建“坡位-土壤-植被”关系是重建山体断面植被功能的有效途径。

三峡库区滑坡工程加固和生态护坡措施研究进展

三峡库区干、支流跨度极广,受地层岩性、岸坡结构、库水波动及强降雨的影响,库区频发以滑坡为主的地质灾害。结合三峡库区滑坡的分布规律,分析了降雨和库水波动两种主要外因作用下不同工程地质类型滑坡的变形响应特征及失稳机理,总结介绍了三峡库区滑坡灾害治理所采用的抗滑桩支护、挡土墙支护、锚杆(索)加固3种主要工程措施的支护原理和设计计算方法,以及生态护坡技术的加固机理及其在三峡库区的研究试验和推广使用。研究认为:目前三峡库区滑坡治理主要以工程措施为主,一般较少考虑滑坡防治的生态效应,今后的研究可针对三峡库区降雨型滑坡特点,更深入地探索库水波动、强降雨等外因作用下生态-结构复合护坡体系的联合加固机理及设计评价方法。

西北寒旱区高速公路4种边坡防护形式植被恢复效果

在进行高速公路建设时,合理采用边坡防护形式可以很好的提高植被恢复效果。针对寒旱区环境和地质地貌特点,选取三维网植草、蜂巢格室,撒播植草和生态袋植草等4种公路边坡防护形式开展试验研究,通过测量土壤性质变化及植物生长情况探究不同防护形式对土壤环境营造和植物生长的影响。结果表明:4种防护形式都在不同程度上保证了植物生长,但植被恢复效果存在差异。蜂巢格室能够较好的改善土壤条件进而保障植物生长,其次为三维网植草,植被恢复效果较差的为撒播植草和生态袋防护形式。对于寒旱区高速公路边坡植被恢复宜采用蜂巢格室的防护形式,而对于有坡面稳定需求的边坡宜采用生态袋防护形式。

干旱半干旱区岩质边坡生态基材防护特性与优化配比

为修复干旱半干旱区岩质边坡的生态系统,获得生态护坡基材的优化配比,以一种新型生态基材为研究对象,以黏结剂、木纤维、保水剂为3个因素,各取3个水平,开展多指标多因素正交试验探索各因素和水平对基材性能的影响规律。结果表明:黏结剂可以有效提升基材的强度和水稳性能,与适量水分作用可以发挥最优效能。随其掺量的增加,抗剪强度表现为先增加后减小,渗透系数和崩解量均表现为减小;施用较少剂量的保水剂即可对基材的渗透、持水性能产生较大的影响,有效提高基材固持自然降水的能力;木纤维与黏结剂的相互作用,可以促进其对基材的加筋补强和改善土壤构型效能的发挥,增强基材的抗冲抗剪性能。除渗透系数随木纤维掺量的增加而增加外,其他指标均呈先增大后减小的趋势。由极差分析可得,各因素对基材性能的影响程度表现为黏结剂>木纤维>保水剂,获得基材的最优配比为黏结剂3%,木纤维4%,保水剂0.1%,最优含水率为16%。