Open AccessThe Effect of Determination of Ground Conditions on Expressway Embankment Foundation
Author(s) -
Stanisław Majer
Publication year - 2019
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/603/3/032069
Subject(s) - levee , foundation (evidence) , investment (military) , reinforcement , geotechnical engineering , civil engineering , soil water , environmental science , engineering , computer science , structural engineering , law , soil science , politics , political science
Proper identification of ground conditions is one of the most important stages of preparing building documentation. This stage becomes even more important when there are organic soils in the building site. The article discusses a case study of the foundation reinforcement of the expressway embankments with existing thick organic soils layers underneath. This investment was carried out in the “Design and Build” formula. Therefore, the materials made available by the Investor at the stage of preparing the offer determined the method of strengthening the weak substrate by the Contractor. Since the basic criterion for selecting the offer to complete the investment was the price, the choice of the reinforcement method had an impact on the overall cost of execution. This problem concerned about 730 m of an expressway passing through the valley. The height of the embankments was from 3 to 5.5 m, the area of the embankment’s base was about 26 500 m 2 and the average depth of occurrence of weak soils was 10 m. The situation was additionally complicated by the bridge located in the missile of the section, that was based on driven piles. In the described case, the depth of occurrence of the support substrate was determined correctly, inaccuracies occurred when determining the type of organic soils and, above all, determining their state and shear strength. An additional wide range of field and laboratory tests performed during the implementation of the project, commissioned by both the contractor and the contracting party, has changed the method of ground reinforcement. The original Controlled Modulus Columns with a diameter of 40 cm in a triangular spacing with a length of over 90,000 m have been changed to precast reinforced concrete piles with a 40 x 40 cm cross-section in a square spacing with a total length of more than 57,000 m. The head of the columns was finished with a 30 cm C30/37 reinforced concrete slab instead of a transmission layer of aggregate and geosynthetics.