Comprehensive Study Of Operating Characteristics Of Long-span And High-fill Highway Culvert

Highway culvert is one important part of the project, in terrains area average of about4to6(Block) per kilometer. However culvert project did not get the attention it deserves, in thedesign of the reference plane only Geological Survey topographic maps and engineering data,and did not pay attention culvert design theory, ignoring the culvert structure and the soil is acommon task is statically indeterminate structure mechanism, resulting in the generation ofculvert, seriously affected the normal operation of the highway. This article relies on adomestic long-span high fill culverts, through theoretical analysis, numerical simulation andthe necessary engineering example, long-span high fill culvert operating characteristicscomprehensive study achieved the following results:1. Currently, culvert highway specification vertical earth pressure for the soil columnpressure, the pressure is less than the actual subject of the culvert, so culvert structure is in anunsafe condition; Meanwhile, foundation and foundation engineering design by means of civilengineering highway culvert engineering principles of foundation bearing capacity is less thanthe base pressure, which leads to two problems: First, it is not enough if the bearing capacityof foundation treatment, a result, the better the foundation treatment, foundation bearingcapacity to meet, but the role of the culvert top The vertical earth pressure is exceeded, themore pressure the soil column. Second, high fill large span culvert project, the foundationbearing capacity is generally calculated using the highway design specifications willobviously not enough, mainly depth values wrong, this is the specification does not considerthe operating characteristics of the culvert reasons. In this paper, after analysis: To designspecification foundation bearing capacity formula is corrected, the foundation bearingcapacity after correction will be higher than the current design bearing capacity. In short, notonly on the road specification less vertical earth pressure calculation, the foundation bearingcapacity less considered, this paper conducted a study and correct, and actual project as thebasis for verification.2. The formula involves culverts vertical earth pressure famous are20kinds of differentfactors to consider each and currently applicable scattered many formulas, it still lackstheoretical calculation of earth pressure on culverts unified finishing induction. This paper was carried out combing, analysis, verification, explains the advantages and disadvantages ofeach of the applicable conditions and can provide a reference for the application. And throughan engineering example, the existing culvert vertical earth pressure calculation theories andmethods of comparative commentary.3. Culverts and soil interaction is statically indeterminate structure, when the structure isdesigned to load, you must first determine what conditions should belong to the appropriatechoice of vertical earth pressure calculation formula. Existing common mechanism modelculverts and soil are focused on one aspect from the analysis of the culvert top soil pressure,due to the different characteristics of the actual project which is different, Han body stiffness,foundation stiffness, laying forms and Fill nature and so have an important impact on theearth pressure culvert roof. Current lack of analytical models for the existing culvert soil, thispaper presents the "quality scissors bomb" model, which can fully reflect the culvert soilmechanism of action, to solve mechanical problems most culverts and soil interaction.4. Relying on engineering design, on the one hand, the design side using conventionalmethods in calculating the bearing capacity of the foundation, there is no substantive basis forunderstanding the depth of embedment, depth values do not meet the culvert forcecharacteristics. In fact, civil engineering is embedded after digging the foundation pit, andculvert construction project is usually good after culverts landfill soil on it, and its essence isdifferent. Resulting in a formula-based embedded depth was significantly smaller values, sothe results can not satisfy the requirements of foundation bearing capacity, not by design, buton the other hand, according to the traditional square design theory that the earth pressureequal culvert top soil column pressure, that is considered to meet the design requirements. Forhigh fill culverts, these theories are not applicable, is wrong.If designers follow the actual culvert earth pressure to bear on the culvert structuredesign, the size of the culvert structures, reinforcement, etc. will be significantly increased,while the culvert structure itself will be very heavy, close to the physical structure. This worksregardless of the actual economic, practical, beautiful and so it is inappropriate. To solve thisproblem the design side facing in this chapter and in accordance with a number of domesticand international research group, proposed the "earth pressure adjustment" measures, namelythe laying of culvert EPS board in the top of a certain range. In order to advance in the pre-construction master "earth pressure adjustment" results, we use finite element software tosimulate this, load variation on the large span under high embankment culverts and culvertmechanism of soil analysis.In order to design successful completion of the construction of this culvert project,proposed for this culvert earth pressure adjustment programs implemented rules. EPS boardmaterial itself on the requirements laid thickness, position, and so do the detailed instructions.For the smooth conduct of construction provides a strong guarantee.