scholarly journals Probabilistic Assessment of Bored Pile Wall: A Slope Stabilisation Technique

2018 ◽  
Vol 203 ◽  
pp. 04006
Author(s):  
Sadaf Qasim ◽  
Danish Kazmi ◽  
Indra S.H. Harahap ◽  
Muhammad Imran ◽  
Abdul Razzaque Sandhu

One of the potential applications of bored piles is the construction of a retaining wall where the piles are closely installed and the spacing between them is often grouted to build a waterproof retaining wall. Based on previous experience, it is observed that the selection of an appropriate retaining structure is crucial to the strength and stability of a structure, provided that the design of retaining structure is adequate and it satisfies the structural requirements. This study considers a Malaysian slope, Bukit Antarabangsa, to perform the probabilistic stability analysis of bored piles. Statistical tools of FORM and Monte Carlo are used to demonstrate the influence of soil parameters on the reliability levels of structure. This paper also presents the load and resistance factors which are developed to counter the rotational and flexural failure modes of a bored pile wall. It is expected that this study will provide a support to the Malaysian geotechnical industry to integrate a reliability-based design for slope construction.

2017 ◽  
Vol 14 (1) ◽  
pp. 53
Author(s):  
Arwan Apriyono ◽  
Sumiyanto Sumiyanto ◽  
Nanang Gunawan Wariyatno

Gunung Tugel is an area that located Patikraja Region, Southern Banyumas. Thetopography of the area is mostly mountainous with a slope that varies from flat to steep. Thiscondition makes to many areas of this region potentially landslide. In 2015, a landslideoccurred in Jalan Gunung Tugel. The Landslide occurred along 70 meters on the half of theroad and causing traffic Patikraja-Purwokerto disturbed. To repair the damage of the road andavoid further landslides, necessary to analyze slope stability. This study is to analyze landslidereinforcement that occurred at Gunung Tugel and divides into 3 step. The first step is fieldinvestigation to determine the condition of the location and dimensions of landslides. Thesecond step is to know the soil parameters and analyzes data were obtained from the field. Andthe final step is analyzed of the landslide reinforcement by using data obtained from thepreceding step. In this research, will be applied three variations of reinforcement i.e. retainingwall, pile foundation and combine both of pile foundations and retaining wall. Slope stabilityanalysis was conducted using limit equilibrium method. Based on the analysis conducted onthe three variations reinforcement, combine both of pile foundations and retaining wall morerecommended. Application of and combine both of pile foundations and retaining wall is themost realistic option in consideration of ease of implementation at the field. From thecalculations have been done, in order to achieve stable conditions need retaining wall withdimensions of 2 meters high with 2,5 meters of width. DPT is supported by two piles of eachcross-section with 0.3 meters of diameter along 10 meters with 1-meter in space. Abstrak: Gunung Tugel adalah salah satu daerah yang terletak di Kecamatan PatikrajaKabupaten Banyumas bagian selatan. Kondisi topografi daerah tersebut sebagian besar berupapegunungan dengan kemiringan yang bervariasi dari landai sampai curam. Hal inimenyebabkan banyak daerah di wilayah Gunung Tugel yang berpotensi terjadi bencana tanahlongsor. Pada tahun 2015, peristiwa longsor kembali terjadi di ruas Jalan Gunung Tugel.Kelongsoran yang terjadi sepanjang 70 meter pada separuh badan jalan tersebut menyebabkanarus lalu lintas patikraja-purwokerto menjadi terganggu. Untuk memperbaiki kerusakan jalandan mencegah kelongsoran kembali, diperlukan analisis perkuatan tanah terhadap lerengtersebut. Studi analisis penanggulangan kelongsoran jalan yang terjadi di Gunung Tugel inidilakukan dengan tiga tahapan. Tahapan pertama adalah investigasi lapangan untukmengetahui kondisi lokasi dan dimensi longsor serta mengambil sampel tanah di lapangan.Tahap kedua adalah melakukan pengujian parameter tanah dan analisis data yang diperolehdari lapangan. Tahapan yang terakhir adalah analisis penanggulangan longsor denganmenggunakan data yang diperoleh dari tahapan sebelumnya. Pada penelitan ini, akanditerapkan tiga variasi perkuatan lereng yaitu dinding penahan tanah (DPT), turap dan DPTyang dikombinasikan dengan pondasi tiang. Analisis stabilitas lereng dilakukan dengan metodekeseimbangan batas. Berdasarkan hasil analisis yang dilakukan terhadap ketiga variasiperkuatan, DPT dengan kombinasi tiang pancang lebih direkomendasikan. Penerapan DPTyang dikombinasikan dengan minipile merupakan pilihan yang paling realistis denganpertimbangan tingkat kemudahan pelaksanaan di lapangan. Dari perhitungan yang telahdilakukan, untuk mencapai kondisi stabil diperlukan DPT dengan dimensi tinggi 2 meterdengan lebar bawah 2,5 meter. DPT tersebut ditopang oleh dua tiang tiap penampangmelintang dengan diameter 0,3 meter sepanjang 10 meter dengan jarak antar tiang 1 meter.kata kunci: tanah longsor, perkuatan tanah, metode keseimbangan batas


Author(s):  
Andrew Lees ◽  
Michael Dobie

Polymer geogrid reinforced soil retaining walls have become commonplace, with routine design generally carried out by limiting equilibrium methods. Finite element analysis (FEA) is becoming more widely used to assess the likely deformation behavior of these structures, although in many cases such analyses over-predict deformation compared with monitored structures. Back-analysis of unit tests and instrumented walls improves the techniques and models used in FEA to represent the soil fill, reinforcement and composite behavior caused by the stabilization effect of the geogrid apertures on the soil particles. This composite behavior is most representatively modeled as enhanced soil shear strength. The back-analysis of two test cases provides valuable insight into the benefits of this approach. In the first case, a unit cell was set up such that one side could yield thereby reaching the active earth pressure state. Using FEA a test without geogrid was modeled to help establish appropriate soil parameters. These parameters were then used to back-analyze a test with geogrid present. Simply using the tensile properties of the geogrid over-predicted the yield pressure but using an enhanced soil shear strength gave a satisfactory comparison with the measured result. In the second case a trial retaining wall was back-analyzed to investigate both deformation and failure, the failure induced by cutting the geogrid after construction using heated wires. The closest fit to the actual deformation and failure behavior was provided by using enhanced fill shear strength.


2011 ◽  
Vol 62 ◽  
pp. 21-35 ◽  
Author(s):  
Anis Ben Abdessalem ◽  
A. El Hami

In metal forming processes, different parameters (Material constants, geometric dimensions, loads …) exhibits unavoidable scatter that lead the process unreliable and unstable. In this paper, we interest particularly in tube hydroforming process (THP). This process consists to apply an inner pressure combined to an axial displacement to manufacture the part. During the manufacturing phase, inappropriate choice of the loading paths can lead to failure. Deterministic approaches are unable to optimize the process with taking into account to the uncertainty. In this work, we introduce the Reliability-Based Design Optimization (RBDO) to optimize the process under probabilistic considerations to ensure a high reliability level and stability during the manufacturing phase and avoid the occurrence of such plastic instability. Taking account of the uncertainty offer to the process a high stability associated with a low probability of failure. The definition of the objective function and the probabilistic constraints takes advantages from the Forming Limit Diagram (FLD) and the Forming Limit Stress Diagram (FLSD) used as a failure criterion to detect the occurrence of wrinkling, severe thinning, and necking. A THP is then introduced as an example to illustrate the proposed approach. The results show the robustness and efficiency of RBDO to improve thickness distribution and minimize the risk of potential failure modes.


Author(s):  
Alex Micael Dantas de Sousa ◽  
Yuri Daniel Jatobá Costa ◽  
Luiz Augusto da Silva Florêncio ◽  
Carina Maria Lins Costa

abstract: This study evaluates load variations in instrumented prestressed ground anchors installed in a bored pile retaining wall system in sandy soil. Data were collected from instrumentation assembled in the bonded length of three anchors, which were monitored during pullout tests and during different construction phases of the retaining wall system. Instrumentation consisted of electrical resistance strain gauges positioned in five different sections along the bonded length. Skin friction distributions were obtained from the field load measurements. Results showed that the skin friction followed a non-uniform distribution along the anchor bonded length. The mobilized skin friction concentrated more intensely on the bonded length half closest to the unbonded length, while the other half of the bonded length developed very small skin friction. The contribution of the unbonded length skin friction to the overall anchor capacity was significant and this should be accounted for in the interpretation of routine anchor testing results. Displacements applied to the anchor head were sufficient to mobilize the ultimate skin friction on the unbonded length, but not on the bonded length. Performance of loading-unloading stages on the ground anchor intensified the transfer of load from the unbonded length to the bonded length. Long-term monitoring of the anchor after lock-off revealed that the load at the anchor bonded length followed a tendency to reduce with time and was not significantly influenced by the retaining wall construction phases.


Author(s):  
Bach Duong

Unexpected defects of concrete in a completed bored pile can arise during the construction stage. Therefore, post-construction testing of bored pile concrete is an important part of the design and construction process. The Cross-hole Sonic Logging (CSL) method has been the most widely used to examine the concrete quality. This method requires some access tubes pre-installed inside bored piles prior to concreting; the required quantity of access tubes has been pointed out in few literatures and also ruled in the national standard of Vietnam (TCVN 9395:2012). However, theoretical bases aiming to decide the required quantity of access tubes have not been given yet. A probability approach is proposed in this paper aiming to determine the essential quantity of access tubes, which depend not only on pile diameters, magnitude of defects, but also on the technical characteristics of CSL equipment. Keywords: access tubes; bored piles; CSL method; defects; inspection probability.


2013 ◽  
Vol 438-439 ◽  
pp. 1427-1432
Author(s):  
Qian Xu Liao ◽  
Jin Cao ◽  
Jun Wei Tang

This paper derives a numerical simulation of direct shearing test and model pile test based on the measured data of bored piles. Characteristics of the interface between bored pile and soil around it are analyzed. Laws of the magnitude and the distribution range of point resistance and frictional resistance of the bored piles in granular and clayey soil are obtained and the mechanism on them is explained.


2011 ◽  
Vol 255-260 ◽  
pp. 602-606
Author(s):  
Long Fei Cheng ◽  
Lin Yan Li

Masonry retaining structure consists of precast concrete blocks, which has good looks and is in harmony with environment. Blocks with proper shape can be used in fluctuating belt of the reservoir area. The construction of masonry structure should conform to the following steps: first, excavate the foundation ditch, lay a cushion and arrange the controlling points, insuring the quality of the first layer of blocks; it would be better to choose inorganic coarse-grained soil as filler and to set a water filtering layer with a height more than 30cm behind the retaining wall; carry on the construction of earth filling behind the wall after the blocks are fixed as requested, and then fix the geotechnical grille when the height of earth filling reaches the elevation of the grille; put Geotechnical Fabric between permeable aggregate and the earth filling behind it to keep the two materials from mixing.


2018 ◽  
Vol 46 (3) ◽  
pp. 284-296 ◽  
Author(s):  
Fei Song ◽  
Huabei Liu ◽  
Liqiu Ma ◽  
Hongbing Hu

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