有关隧道代替陡坡路堑构想

1、有关隧道代替陡坡深路堑的构想 陡坡路堑可能引起稳定性问题，而且陡坡路堑一般还需要结构上的加固。建筑成本是其高度平方的函数，如果高度超过40米或50米，则不会是最经济的方案。尽管可以采用各种措施以改善，但是在某些特殊地段，挡土墙或岩石陡坡对环境的影响是不能容许的；而且养护费用也很高。假使路线低于底面到了足够的高度，可以采用隧道或者随挖随填方法，这样可以少建挡土墙，节省建筑成本。 隧道不仅能通行，又能防止噪音。在通过住宅区时是迫切需要建隧道增加成本来减少对周边的影响是有必要的。 在其他情况下，从施工的角度来看待的话，明挖方案是比较理想化的，因为挖出的土石方材料可以用于填筑路堤，石料可以用做抛石河岸

2、护堤。从地形因素来说：公路路基设计规范（JTG D302004）规定，大于20m的路堑视为深路堑，需要单独勘察。深路堑的土石方数量大，占地多，施工困难，边坡稳定性差，行车不利，应尽量避免使用，不得已而一定要用时，应进行个别特殊设计。隧道一直是一种明显的穿越山岭障碍的方案（高山隘口），而且在山岭地区，占地少，还有一下经济上的优点：避免破坏或改建已建在山谷中的可利用的有限面积上的建筑物和通讯设备。缩短了路线，从而缩短了运行时间（这经常是主要的效益）；降低坡度（对于重型货车，这是很重要的）；在处于边坡不稳定（旧的或活跃的坍坡的地区）或处于稳定限度边缘等地区的情况下，可以避免大量的土石方工程；消除那些

3、为要保持在高海拔地区的道路常年营运而出现的险情、额外开支和困难。随着燃料价格的上涨，上述这些已知优点变得愈加明显。近年来，人们所要求的保护自然环境、避免山谷中已有的各部分（房屋，农业和通讯设备）遭受损失和维护农村观瞻一成为采用隧道的有利因素。特别是在山区，新线可沿山谷两侧而行，并采用隧道通过山嘴。从地基的影响来分析:在深挖路堑边坡当中挖方过多，对路基方面影响没有隧道那么大。隧道的设计和施工很大程度上取决于地基的性质和状况。对于明挖的引进道路的边坡应考虑的因素与隧道门处的相同（粘结力和工作、极限强度摩擦角、流网、基床走向，或岩石的主要断裂）；对于随挖随填隧道，除了上述因素外，还要考虑在施工期间地

4、基形变的特性、短期的稳定性、与土壤颗粒尺寸和排水系统有关固结状况；有关钻掘隧道的施工方法则取决于以下许多参数：对于无支撑工作面，直立时间只能从类似地质中所获得的经验中来确定，或者从造价高昂的导洞坑道中获得；天然地基的水文地质；与挖掘方法有关的因素（耐磨度，可钻性，场地规划）；震动时颗粒的最高速度；在最终衬砌前为保持足够稳定性所需的临时支撑。在隧道成本中，这是变化最大的项目，取决于地基地质特性和其他主要情况（覆盖厚度，有水或无水）；成本分析通过对边坡防护的设计改变和工程项目的增减，必然引起工程 量的变更。影响项目的成本为此作为业主必需对项目进行成本分析 。近几年 ，结合其他几个项目在边坡防护中的

5、经验和教训，挖左边坡应该是防护中的重点和难设计施工时处理得好将一劳永逸，不然营运之后再来养护和维修或返工，将给养护工作带来很大的工作，成浪费和引起再投资，这样的成本比一次就做好要高得多。施工时期深挖的土石方数量是一个巨大的数据，同时由于深挖高度过大，造成了工程许多的不稳定性因素与潜在的危险性。在深挖边坡比的选择上和开挖的工具选择上跟工程后容易发生滑坡、坍塌事故有着必然的联系。与此同时，深挖路堑还伴随着建立起挡土墙来进行支挡。深挖路堑的成本组成：开挖土石方价格，建立支挡结构物的价格，后期维护边坡价格，治理边坡的价格。隧道造价平均1m为3w7w之间，相对于深挖路堑的成本来说，二者相差不大。深挖路堑

6、突出特点需要后期维护，且伴随着不稳定性边坡危害情况，需要人员定期去观测。隧道突出的特点，隧道开挖完后，由于使用现浇混凝土钢结构或预制管片拼装来代替开挖的土石方支撑山体结构，稳定性较好。较长隧道需要安装照明灯。对此，隧道代替深挖路堑构思是完全可行的。长短隧道的选择连续短隧道具有减少通讯问题的优点，可是隧道门之间要有足够的距离。另一方面，短隧道需要重复建造入口（边坡和引道的挖掘、增加照明设备和环境的制约），因而增大成本。 长短隧道见的差别涉及到环境和设备费用。长隧道修建与地下较深处。除了隧道口附近地区外，不受环境制约，而短隧道即使在外面，也会因盖层较浅而受到制约。隧道长度对其成本既有积极影响，也有

7、消极影响：一方面，隧道增长，效益就会增加，这是因为设备投资的回收较快。另一方面，隧道过长，为了缩短工期，常常需要两端同时掘进；而在粒状土中，甚至还需要打中间竖井以便检查盾构方位。最重要的是，隧道加长，就会加大安全和通风设备的费用，土木工程量（竖井，断面扩大，机房）也就会增加。 最后，隧道特短也有困难，而且照明费用也高。最好是在进口处就能看见出口，所以选用直线，最低限度应采用半径大的曲线。 结语：随着公路事业的进一步发展，以及向山区发展的战略目标，深挖路堑边坡与隧道方案选择上仍是一个重要课题。以往由于受到施工工艺和设备的限制 ，出现深挖路堑边坡的情况较多，随着隧道施工设备的完善，隧道对地形占地面

8、积少，施工不受天气影响，隧道施工技术的不断完善，进一步减少成本，保证公路顺畅，驾驶舒适，节约成本。如何进一步完善挖方边坡设计和施工与隧道方案比较，仍需要公路建设者们不断探索和实践，我们要在不断的工程实践中总结经验大力推广隧道设计与施工。RelevantTunnel Instead Of Steep Deep CutSteep slope cutting may cause problems, and the stability of roadbed generally need steep structural strengthening. Construction cost is the h

9、eight of the function, if the height square more than 40 or 50 meters is the most economical solutions. Although it can be adopted various measures to improve, but in some special area, retaining wall rock hills or environmental impact is not allowed, And the maintenance cost is high. If the route t

10、o the floor below, can adopt high enough to dig tunnels or over with so that I can get a method to build the retaining wall, construction cost savings.Tunnel can prevent traffic noise. When is in urgent need by residential building to reduce cost, increase tunnel surrounding effect is necessary.In o

11、ther cases, from the perspective of construction, Ming dig scheme is more idealistic, because the material can be used in the rock embankment conditions, stone can be used on the Banks of the stone.From the terrain factors for:The highway roadbed design specification (2004) D30 JTG, than 20m cutting

12、 as deep cut, requires a separate survey. Deep cut conditions, large quantities of construction, covers an area of difficulty, slope stability, driving, should avoid to use, and must use, should carry out the individual special design.Tunnel has been a clear across the mountains of the scheme (mount

13、ain pass obstacles in the mountain area), but less, and the area, the economic advantages:- avoid damage or modification already built in the valley of the limited space available in buildings and communications equipment.- shortened route, so as to shorten the time (this is often the major benefit)

14、,- for heavy trucks (lower slope, this is very important),- in the slope instability (old or the active region of slope stability limits or in the edge of the area and circumstance, can avoid the conditions of engineering,For to keep, eliminate the road at high altitudes of danger and the perennial

15、additional expenses, and difficulties.With fuel prices, these advantages becomes more and more obvious known.In recent years, people required to protect the environment and to avoid the valleys existing parts (houses, agriculture and communications equipment maintenance and losses) as adopted a rura

16、l much more favorable factors of the tunnel.Especially in the mountainous area, the line along the valley and can be adopted, and both ShanZui through the tunnel.From the foundation of the effect to analyze:In the deep excavation of the appraise of slope dig for subgrade effect overmuch, no tunnel.

17、The design and construction of the tunnel depends largely on the foundation of the nature and the status.For the introduction of the slope dig road tunnel and the factors to be considered in the same (the door and ultimate strength, cohesion, friction Angle, discusses the bed rock, or the main fract

18、ure),To dig with tunnel, with the above factors, but also consider during construction foundation deformation characteristics, short-term stability, and the soil particle size and drainage system status,Dig tunnel construction related drilling under law depends on a number of parameters:For no suppo

19、rt from working time, erect only similar geology of experience to determine, or from the cost of the high strain of tunnel.Natural foundation - the hydrogeology,With the mining method, relevant factors (wear-resisting degree, drillability, venue planning),When the particle vibration - the highest sp

20、eed,In the end, to maintain the stability of enough before lining for temporary support. In the tunnel of cost, this is the biggest change, depends on the foundation of the projects and other major geological characteristics (cover thickness, water or water),Cost analysisThrough the design of slope

21、protection and project, the project quantity change must cause. The cost of this project to project owners as necessary cost analysis. In recent years, with several other projects in slope protection of experience and lessons,Dig left the key protective slope is difficult to design and construction

22、of good processing operations, otherwise will once again after to conserve and maintenance or rework, will give the maintenance work of the great work, into the waste and cause more than the cost of investment, this was a much higher. Construction of the deep cut conditions is a huge amount of data,

23、 at the same time, because of excessive height, dig deep caused by many factors of instability engineering and potentially dangerous. In the deep cut slope excavation than on the choice of the tools and to select landslide, after the project to collapse are inevitable connection. Meanwhile, deep cut

24、 cutting with retaining wall to establish a block. To dig deep excavation of cost cutting conditions: the price, the price of retaining structures, maintenance and management of slope slope price price.Average cost of tunnel for 3w - moksan 0.7w power between the 1-m relative to dig deep, cutting co

25、sts, both.To dig deep cutting prominent characteristics, and maintenance with slope stability, need to harm to observation regular staff.Prominent characteristics of tunnel excavation, tunnel, because after using cast-in-situ concrete prefabricated segments steel structure or assembled to replace th

26、e excavation supported by structure, stability conditions. A long tunnel need to install lighting.To dig deep tunnel, instead of cutting is completely feasible.Length of the tunnelContinuous short tunnel has the advantages of reducing communication problem, but the tunnel gate between enough distanc

27、e. On the other hand, short tunnel construction entrance (need to repeat the word and slope excavation, increasing lighting equipment and environment restriction), thus the cost.See the difference between length of tunnel is related to environmental and equipment costs. Long tunnel and underground i

28、s built. Besides the region near the slope, do not suffer environmental constraints, and short tunnel even outside, also can cover by shallow and restricted.The cost of tunnel length has both positive and negative effects:On one hand, the tunnel, the benefits would increase growth, because the equip

29、ment investment recovery quickly.On the other hand, the tunnel is too long, in order to shorten the construction period, often need ends and excavation, While in granular soil in the middle, even to play for the inspection shaft shield.The most important is, tunnel extended, would increase the cost of the equipment, safety and ventilation quantities (vertical section, civil engineeri