砂泥岩混合料填筑体在湿化条件下的沉降特征研究

发布时间：2018-01-23 01:19

本文关键词： 填筑体砂泥岩混合料湿陷沉降数值模拟沉降变形　出处：《成都理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：近年来我国西南部地区经济受国家整体经济的发展和西部大开发战略实施的影响不断快速发展,经济的高速发展也带动了西南部地区基础设施建设的不断加强。西南地区机场、铁路、高速公路的建设也进入了发展的高峰期,而航空运输业因其所具有的诸多优势,因而成为重点的发展方向。机场建设由于其本身的场地范围广、面积大,因而必然涉及到的工程问题也多。再加之西南地区地形地貌多样,以山地、丘陵和沟谷为主,自然地理地质条件复杂。以上这些因素都使得西南地区机场建设的设计和施工都面临相当复杂的工程问题。西南地区红层分布广泛,这一地区工程当中填料往往是就地取材,因而高填方填筑体多是将场区内岩石经爆破后产生的碎石料经人工填筑压实而成。机场高填方往往在工后出现较大的沉降并引发不均匀沉降问题,其中一个突出的问题就是砂泥岩混合料填筑体的湿陷沉降。本文将选取机场高填方填筑体在湿化条件下的沉降特征问题进行研究和探讨。以重庆新机场砂泥岩碎石土混合料作为试验研究对象,对其进行试验研究,并结合昆明新机场T7段已出现的湿陷沉降问题作为工程实例进一步阐明高填方填筑体在湿化条件下的沉降特征。本文的主要结论和成果为:湿陷沉降的机理包含以下几个方面:(1)湿化条件下砂泥岩碎石土的强度有所下降并出现颗粒的重新排列;(2)泥岩存在着遇水崩解软化的性质,大颗粒的泥岩遇水崩解成为细小的泥岩颗粒,泥岩的这一性质也是导致砂泥岩混合料湿陷沉降的重要因素;(3)水分的润滑作用使得砂泥岩颗粒间的摩擦力下降,使得砂泥岩颗粒之间出现了滑移和错动。通过室内试验,也验证后两点对湿陷沉降影响更为显著。对昆明新机场T7段出现的湿陷沉降进行研究,提出沉降预测的方法以及避免湿陷沉降的工程措施。(1)对于填料的种类与级配的恰当选择,尽量避免或减少使用泥岩等易发生遇水崩解的材料作为填筑料;(2)在填方体的施工过程中需要进行强夯处理确保填筑料的压实度;(3)控制细微颗粒物占到填筑料的比例,细微颗粒物占填筑料的比例过大将加大填筑体的湿陷沉降量。
[Abstract]:In recent years, the economy of southwest China has been developing rapidly under the influence of the development of the whole national economy and the implementation of the western development strategy. The rapid development of economy has also led to the continuous strengthening of infrastructure construction in the southwest. The construction of airports, railways and highways in southwest China has also entered the peak period of development. Because of its many advantages, the air transport industry has become a key development direction. The airport construction has a wide range of sites and large area. Therefore, there must be many engineering problems involved. In addition, the southwest region has a variety of topography and landforms, mainly mountainous, hilly and gully. These factors make the design and construction of the airport in the southwest face quite complex engineering problems. The red beds are widely distributed in the southwest. In this area of engineering, the packing is often based on local materials. As a result, most of the high fill fill is made by artificial filling and compaction of the rock in the field area after blasting. The airport high fill often occurs a large settlement after construction and causes uneven settlement problem. One of the outstanding problems is the settlement of sand and mudstone mixture. In this paper, the settlement characteristics of airport high fill under humidification condition are studied and discussed. Stone and soil mixture as experimental research object. The experimental study was carried out. Combined with the problem of settlement in T7 section of Kunming New Airport as an engineering example, the settlement characteristics of high fill under wet condition are further clarified. The main conclusions and results of this paper are as follows:. The mechanism of subsidence includes the following aspects: (. 1) under humidification condition, the strength of sand and mudstone gravel soil decreased and the grain was rearranged; (2) the mudstone has the property of water collapse and softening, and the large grain mudstone disintegrating into fine mudstone grain, and this property of mudstone is also an important factor leading to the settlement of sand and mudstone mixture. 3) the lubricating effect of moisture makes the friction between sand and mudstone particles decrease, and makes the sand and mudstone particles slip and stagger. It is also verified that the effect of the latter two points on the subsidence is more significant. The subsidence occurred in the T7 section of Kunming New Airport is studied. The method of settlement prediction and the engineering measures to avoid collapsing settlement are put forward. The proper selection of packing type and gradation should be made to avoid or reduce the use of materials such as mudstone which are prone to water collapse as filling materials. 2) it is necessary to carry out dynamic compaction to ensure the compaction degree of the filling material during the construction process of the filling body; 3) controlling the proportion of fine particulate matter to the filling material, and if the proportion of fine particulate matter to the filling material is too large, the settlement of the filling body will be increased.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU43

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