Deflection behavior of the nailed slab system-supported embankment on peat soil

Abstract

556 INTRODUCTIONThe main characteristics of peat soil are high compressibility, low shear strength, and high moisture content [01]. Such characteristics pose problems if peat soil is used as a subgrade construction. Several methods to improve peat soil include soil replacement, reinforcement to improve soil strength and stiffness, preloading and stage construction, soil improvement, stone columns, piles, and mixing of chemicals such as cement and lime [02]. Sand fi ll on peat soil can improve parametric values of peat soil. Adding the thickness of sand on peat soil will increase the value of subgrade reaction modulus and the modulus of deformation [03]. Deposition of fi ll with better soil types can be performed on peat soil, but its implementation may encounter several problems. Some problems include excessive lateral movement, heave occurring on deposit of soft soil and the formation of mud wave, mixing of fi ll with the very soft soil, and differential settlement, as in [04]. The large deformation took place together with tension cracks and heave when the height of embankment rapidly increased [05]. Secondary settlement can be reduced by surcharging [06]. The effective method to improve peat soil are preloading and surcharging [07]. Preloading consists of applying a load, equivalent to or greater than a total load of a planned structure, over the site prior to constructing the structure which is being partially or fully removed when the required settlement has taken place. Preloading consisting of loading and unloading methods can accelerate peat soil compression [08]. The increase in OCR on loading and unloading methods for high organic soil can reduce the rate of secondary compression [09]. In addition to reducing compression, preloading can also increase the bearing capacity of peat [10]. The Embankment with stage construction and thin layers can be applied to peat soil to allow consolidation and increase shear strength.Reinforcement can contribute to increasing the stability of embankment, that reinforcement and shear strength of peat will resist lateral forces [11]. Reinforcement with slabs without piles only affects the top layer of the surface with a depth of generally not more than the width of the foundation slab [12]. Slabs can be reinforced by piles to support the embankment. Some of the advantages of the piles in supporting embankment include the implementation of embankment construction can be completed in a short time, embankment-supporting piles can reduce total settlement and differential settlement signifi cantly [13]. In addition, the implementation of the piles corresponds to non-uniform geological conditions. Another alternative use of piles on soft soil is the use of nailed-slab system [14], [15], [16]. Piles affect the increase in modulus of subgrade reaction. The height of piles affects the stiffness of nailed-slab system and the reduction of slab defl ection at the load center. The nailed-slab system generated uniform settlement, increased the strength of subgrade support, improved the...

The potential of liquefaction disasters based on the geological, CPT, and borehole data at Southern Bali Island

“…Some indications show similar phenomena also occur in the Northwest-Southeast and West-East of Bali. Some areas have sedimentary soils, which is very problematic since they, just like peat, have high compressibility and weak shear strength, which need long-term improvement efforts [5]. The research shows that liquefaction occurs in the depth of 3m -15m for Seed et al (1976) method whereas no indication of liquefaction shows from Castro (1975) methods in any depths.…”

Uji Beban Timbunan yang Diperkuat dengan Sistem Pelat Terpaku pada Tanah Gambut

“…Hal yang sama didapatkan pada uji beban timbunan yang didukung oleh sistem pelat terpaku dengan ukuran pelat 60 cm x 28 cm pada tanah gambut (Waruwu et al 2017a). Pemasangan tiang pada pelat mampu mereduksi penurunan dan meningkatkan modulus reaksi tanah dasar.…”

“…Adapun denah dan penampang uji model dapat dilihat pada Gambar 1 dan 2. Sampel gambut yang digunakan sama dengan bahan penelitian sebelumnya (Waruwu et al 2016a;2016b, 2017a2017b). Jenis gambut ini merupakan gambut berserat dengan kadar abu rendah, karena memiliki nilai kadar organik > 75%, kadar serat > 20%, dan kadar abu < 5%.…”

Simplified method for prediction of settlement in bamboo piles-reinforced peat under embankment

“…Embankmenton the ground peat will experience many problems among embankment instability, stability in the lateral direction, overalls sliding, and the excessive settlement ( [9]; [6]). The peat soil has a high moisture content properties, large compression, low shear strength, and low ground bearing capacity [12]. Embankment load as preloading can increase the bearing capacity of peat effectively [7].…”

“…The combination of grid and pile bamboogrid as reinforcement of embankment on peat soil showed the ability in reducing the settlement and the defl ection so that the stability of the embankment is maintained [5]. Installation of piles on a concrete slab to support the embankment is able to reduce the settlement and increase the modulus of subgrade reaction peat [12]. Liu et al [3] states that there are several advantages of piles as supported embankment, such as implementation of embankment construction can be completed in a short time, the pile supported embankmentcan reduce total and settlement signifi cantly, and the technical implementation of the pile corresponding the geological conditions.…”