BEARING CAPACITY IMPROVEMENT OF PEAT SOIL …

1 VOL. 12, NO. 1, JANUARY 2017 ISSN 1819-6608. ARPN Journal of Engineering and Applied Sciences 2006-2017 Asian Research Publishing Network (ARPN). All rights reserved. BEARING CAPACITY IMPROVEMENT OF PEAT SOIL BY PRELOADING. Rika Deni Susanti, Maulana and Aazokhi Waruwu Department of Civil Engineering, Medan Institute of Technology, Indonesia E-Mail: ABSTRACT. Peat soil including soil type has high compression and low BEARING CAPACITY . IMPROVEMENT of peat soil can be done with stabilization using cement, lime and other materials, but it can not be applied at depths below 1 meter.

2 Effective method to improve it is preloading method. Preloading can be applied using embankment material, so it can accelerate the compression and to increase the BEARING CAPACITY of on peat paper describe the results of small-scale model test in laboratory on peat soil before and after preloading. The results showed that the preloading is able to accelerate the compression and increase the BEARING CAPACITY of peat. Keywords: peat, preloading, compression, BEARING CAPACITY . 1. INTRODUCTION and drainage. As a result of preloading, the value of SPT.

3 Peat soils are low shear strength, low BEARING and free compressive strength increases, it indicates that CAPACITY , and high compression. The parameters of density the preloading is effective in improving the soft peaty soil and shear strength of peat is an important factor in the layers. Rowe and Li [8] states that the failure of the pile on stability problem peat soil, reducing compression, top of the peat soil is generally caused by excessive shear reduction of permeability, control the flow of deformation of the pile rather than shifting certain groundwater, and the problem of consolidation.

4 Using of surfaces. Retrofitting can contribute in increasing the the technique of cement columns on peat soil can increase stability of the embankment, where the reinforcement and the shear strength of peat. Examines the use of the shear strength of peat will withstand lateral forces that stabilization of the cement column on peat soil is not work. disturbed. Parameter compression peat soil can be IMPROVEMENT of peat soil can be done with improved by increasing the ratio of cement column [5]. stabilization using cement, lime and other materials, but it Engineering properties of peat soil can be can not be applied at depths below 1 meter, other improved by the use of sodium silica stabilization, improvements using the retrofitting of the layers of stabilization of cement, cement column, and some other geotextile, use the column of cement and other alternative reinforcement materials [6].

5 The nature of this improved is by applying an initial load or preloading. It is expected technique will be able to increase the BEARING CAPACITY of from the application of preloading, compression decreases, these soils. Peat soil BEARING CAPACITY is not reinforced and BEARING CAPACITY will increase. Preloading can be foundation under construction. Large drop will occur on applied using embankment material, so it can accelerate peat soil that is not corrected and the resulting settlement the compression and to increase the BEARING CAPACITY of the in the foundation [4].

6 Foundation on peat soil. Preloading and surcharging is an effective Preloading can be applied using the system method to improve soils [7]. In the soft soil that is easily embankment of sand material. In this paper, we will study compressible and thick like peat, require loading prior to the potential of the preloading of the pile to speed the construction of permanent implemented. This is called compression and increase the BEARING CAPACITY of these giving the initial load or preloading, the purpose of soils. preloading is to eliminate or reduce the settlement of primary consolidation, by loading the soil first before the 2.

7 RESEARCH METHODS. implementation of the building. The advantage of Test material under study is peat soil taken from preloading, except reduce the settlement, it also increases Dumai-Riau. The test results of physical properties of peat the soil BEARING CAPACITY . soil in between specific gravity (Gs) = 1, 25, density ( b) =. Shen et al. [9] used a combination of methods of 12, 14 kN/m3, water content (w) = 612, 08%, organic electro and vacuum-preloading overlying water to prevent content (Oc) = 83,37%, fiber content (Fc) = 25,32%, and deficiency, increasing the BEARING CAPACITY and reduce the ash content(Ac) = 13,63%.

8 This sample has value of compression on the ground, so the design is more organic content> 75% and fiber content> 20%, thus effective. While Chun and Yan [2], using the vacuum including fibrous peat. preloading method to estimate the degree of consolidation Small-scale test model on the box model of width on the ground. 90 cm, length 120, and a height of 90 cm. Peat compacted The behavior of soft soil deposits improved with density approaching the field. On peat given prelaoding vertical drainage and preloading [1]. Hoque et al. [3] load of sand material as high as cm, cm, cm, applying preloading with a pile of compacted silty soil as cm and cm.

9 Dial indicators CAPACITY 50 mm with high as 3 m above ground peaty loam. Between the soft an accuracy of mm was used to measure the soil and pile placed geotextile and sand as reinforcement magnitude of the decline due to preloading. After 121. VOL. 12, NO. 1, JANUARY 2017 ISSN 1819-6608. ARPN Journal of Engineering and Applied Sciences 2006-2017 Asian Research Publishing Network (ARPN). All rights reserved. preloading forwarded to the plate load test with plates 30. measuring 10 cm x 10 cm to get peat soil BEARING CAPACITY . Settlement (cm) Height of embankment (cm).

10 Test scheme can be seen in Figure-1. 25. 20. 15. 10. dial settlement 5. Sand Time (days). 1. 1 0. 0 10 20 30 40. -5. -10. -15. Peat H = 90 cm -20. Figure-2. Time relationship with the settlement due to the preloading. The increase in the rate of settlement due to preloading can be seen in Table-1. As a result of preloading, the compression of peat was accelerated by B = 90 cm increasing the settlement. The settlement reached 77 mm for preloading with sand height cm. This may imply Figure-1. Testing scheme in the laboratory. that the preloading compression due to the peat was accelerated, so that the very high compression of peat 3.