|Agus Setyo Muntohar||Department of Civil Engineering, Faculty of Engineering, Universitas Muhammadiyah Yogyakarta, Jl. Brawijaya, Tamantirto, Bantul, D.I. Yogyakarta, 55183, Indonesia|
|Willis Diana||Department of Civil Engineering, Faculty of Engineering, Universitas Muhammadiyah Yogyakarta, Jl. Brawijaya, Tamantirto, Bantul, D.I. Yogyakarta, 55183, Indonesia|
|Muhammad Yogma Tafalas||Department of Civil Engineering, Faculty of Engineering, Universitas Muhammadiyah Yogyakarta, Jl. Brawijaya, Tamantirto, Bantul, D.I. Yogyakarta, 55183, Indonesia|
|Nakosa Rafa Bimantara|
This paper provides the test results of the load-deformation test on a flexible plate, supported and unsupported by SiCC mortar columns in the laboratory setting. Two columns types were used in this experiment, a circular column (O-shape) and a column with head enlargement (T-shape). The main purpose of this study was to examine the heave of flexible plate due to the swelling effect and modulus of subgrade reaction under a loading-unloading cycle. The expansive soil was put into a testing container with a diameter and height of 550 mm and 1000 mm respectively. The clay thickness was 700 mm and the sand layer was compacted to 200 mm at the bottom of the container. The column diameter (Dc) was 50.8 mm (2 in.), and had a length of 500 mm. The height and diameter of the column head were enlarged to three times the column diameter (3Dc), which was about 152.4 mm (6 in.). Loading tests were performed after 8 days of saturation and 14 days of curing the column. The test results showed that installation of the column in support of the plate reduced the heave to about 16% and 22% respectively for the O-shape and T-shape column-support plates. The T-shape column-strengthened plate can enhance the modulus of subgrade reaction to about 203%. This result indicated significant improvement by the enlarged column head in carrying and transmitting the load to the soil.
Deflection; Expansive soil; Flexible plate; SiCC column technique
Building and road pavement damage on expansive clay soil has become a problem that needs serious treatment. The swelling and shrinking of expansive clay soil will have a considerable effect on the supported construction. Several methods can be applied to increase soil bearing capacity, such as material replacement or soil mixing, the alteration of chemical properties and the use of geosynthetics. Chemically, lime is widely used to stabilize expansive soil at a shallow depth of up to 1 m. Many investigators studied a deep mixing method using lime-columns or lime/cement- columns to strengthen expansive soil, e.g. Tonoz et al. (2003), Rao and Thyagaraj (2003), Hewayde et al. (2005), and Puppala and Pedarla (2017). These researchers explain that the lime or cement column technique can also serve as a mini pile foundation which functions to control the uplift force and deformation. The installation of columns from pozzolans into the subgrade is principally similar to the mini piles (Abiodun and Nalbantoglu, 2015). The columns system can increase the strength and decrease the deformation of the foundation caused by the swelling pressure of expansive soil (Tonoz et al., 2003; Hewayde et al., 2005; Muntohar and Liao, 2006). Active lime columns will absorb the soil moisture to produce hydration reaction in adjacent soil and surrounding column. The calcium ions from lime will penetrate into soil and migrate into the soil surrounding the column and will be enclosed by the lime-column (Abiodun & Nalbantoglu, 2015). The lime column, which is moistened with water, will react more rapidly than the column that is not moistened (Abiodun and Nalbantoglu, 2015; Puppala & Pedarla, 2017). When the columns are applied to support an upper structure, such as pavement, the system can be modeled as a piled-flexible plate (Core and Siddiqui, 2013; Diana et al., 2016; Puri, 2017; Huang et al., 2017).
The previous research, e.g. Abiodun and Nalbantoglu (2015), Damoerin et al. (2015), Tonoz et al. (2003), Hewayde et al. (2005), Muntohar and Liao (2006), mainly used lime or cement columns as a form of deep mixing stabilization. Those studies of lime or cement column were applied as a foundation system for flexible pavement on expansive clay. Hence, this paper introduces a new foundation system for flexible pavement to control the soil heave and enhance the load carrying capacity of the pavement. The purpose of this research is to study the characteristics of a flexible plate supported by the columns on expansive soil as a foundation system.
This laboratory experiment was conducted to evaluate the heave and load deflection of the flexible plate supported with SiCC mortar columns. Two types of columns were used, an O-shape and T-shaped column. In general, this research shows that SiCC column-supported plates on expansive clay can reduce the heave and increase the load carrying capacity. In general, the heave increases with the elapsed time. Installation of the column to support the plate reduces the heave at about 16% and 22% respectively for the O-shape and T-shaped column-support plate. The reduction of the heave can be attributed to the mechanically effect instead of the migration of cations from the SiCC into the soil. The addition of the O-shape column increases the modulus of subgrade reaction slightly by about 18%. However, the T-shape column-strengthened plate can enhance the modulus of subgrade reaction (k) by about 203%. This result indicates a significant improvement by the enlargement of the column head to reduce the heave and carrying and transmitting the load to the soil. However, further study for both large scale and numerical models are needed to confirm this concluding remark.
This paper is part of research sponsored by the Ministry of Research, Technology, and Higher Education in 2014–2017 under the National Strategic Research Grant number DIPA-023.04.2.189971/2014 and DIPA-042.06.0.1.401516/2016.
Abiodun, A.A., Nalbantoglu, Z., 2015. Lime Pile Techniques for the Improvement of Clay Soils. Canadian Geotechnical Journal, Volume 52(6), pp. 760–768
American Society for Testing and Materials (ASTM), 1997. ASTM D1195-93: Standard Test Method for Repetitive Static Plate Load Tests of Soils and Flexible Pavement Components, for Use in Evaluation and Design of Airport and Highway Pavements. ASTM International, Pennsylvania, USA
American Society for Testing and Materials (ASTM), 2008. ASTM D4546-08, Standard Test Methods for One-Dimensional Swell or Collapse of Cohesive Soils, ASTM International, Pennsylvania, USA
Budiman, I., Soedigdo, I., Prakoso, W.A., 2015. Analysis of Suction Piles for Mooring Floating Structure Foundations in Clay Soil at Deepwater Levels. International Journal of Technology, Volume 6(2), pp. 254–263
Core, H.S., Siddiqui, M.J., 2013. Analysis of the Piled Raft for Three Load Patterns: A Parametric Study. Coupled Systems Mechanics, Volume 2(3), pp. 289–302
Damoerin, D., Prakoso, W.A., Utami, Y., 2015. Improving Shear Strength of Clay by using Cement Column Reinforcement under Consolidated Undrained Test. International Journal of Technology, Volume 6(4), pp. 709–717
Diana, W., Hardiyatmo, H.C., Suhendro, B., 2016. Small-scale Experimental Investigation, on the Behaviour of Nailed Slab System in Expansive Soil. In: AIP Conference Proceedings Volume 1755(1)
Hardiyatmo, H.C., 2009. Metoda Hitungan Lendutan Pelat Dengan Menggunakan Modulus Reaksi Tanah Dasar Ekivalen Untuk Struktur Pelat Fleksibel (The Method for Calculation of the Plate Deflection by using the Equivalent Modulus of Subgrade Reaction for the Flexible Plate Structure). Jurnal Dinamika Teknik Sipil, Volume 9(2), pp. 149–154
Hewayde, E., El Naggar, M.H., Khorshid, N., 2005. Reinforced Lime Columns: A New Technique for Heave Control. In: Proceedings of the Institution of Civil Engineers Ground Improvement, Volume 9(2), pp. 79–87
Huang, M., Jiu, Y., Jiang, J., Li, B., 2017. Nonlinear Analysis of Flexible Piled Raft Foundations Subjected to Vertical Loads in Layered Soils. Soils and Foundations, Volume 57(4), pp. 632–644
Liu, S.Y., Du; Y.J., Yi, Y.L., Puppala, A.J., 2012. Field Investigations on Performance of T-shaped Deep Mixed Soil Cement Column–supported Embankments Over Soft Ground. Journal of Geotechnical and Geoenvironmental Engineering, Volume 138(6), pp. 718–727
Malekpoor, M.R., Poorebrahim, G.R., 2014. Behavior of Compacted Lime-soil Columns. International Journal of Engineering Transactions B: Applications, Volume 27(2), pp. 315–324
Muntohar, A.S., 2006. The Swelling of Expansive Subgrade at Wates-Purworejo Roadway, Sta.8+127. Civil Engineering Dimension, Volume 8(2), pp. 106–110
Muntohar, A.S., 2014. Improvement of Expansive Subgrade using Column Technique of Carbide Lime and Rice Husk Ash Mixtures. In: Proceedings Southeast Asia Conference on Soft Soils Engineering and Ground Improvement (SOFT SOILS 2014), Volume 2, pp. I4-1–I4-6
Muntohar, A.S., Liao, H.J., 2006. Strength Distribution of the Soil Surrounding Lime-column, In: Chan, D., and Law, K.T. (Ed.), Proceeding 4th International Conference on Soft Soil Engineering, Volume 1, pp. 315–319
Muntohar, A.S., Hashim, R., 2005. A New Formula for Rate of Swelling of Expansive Clay Soils. Jurnal Semesta Teknika, Volume 9(2), pp. 111–125
Nusier, O.K., Alawneh, A.S., 2004. Micropile Technique to Control Upward Movement of Lightweight Structures Over Expansive Soils. Geotechnical and Geological Engineering, Volume 22, pp. 89–104
Puppala, A.J., Pedarla, A., 2017. Innovative Ground Improvement Techniques for Expansive Soils. Innovative Infrastructure Solutions, Volume 2, pp. 24–39
Puri, A., 2017. Developing Curve of Displacement Factor for Determination of Additional Modulus of Subgrade Reaction on Nailed-slab Pavement System. International Journal of Technology, Volume 8(1), pp. 124–133
Rao, S.M., Thyagaraj, T., 2003. Lime Slurry Stabilization of an Expansive Soil. Geotechnical Engineering, Volume 156(3), pp. 139–146
Soundara, B., Robinson, R. G., 2017. Hyperbolic Model to Evaluate Uplift Force on Pile in Expansive Soils. KSCE Journal of Civil Engineering, Volume 21(3), pp. 746–751
Tonoz, M.C., Gokceoglu, C., Ulusay, R., 2003. A Laboratory-scale Experimental Investigation on the Performance of Lime Columns in Expansive Ankara (Turkey) Clay. Bulletin of Engineering Geology and Environment, Volume 62(2), pp. 91–106