Effect Of Shear Strength Parameters In Residual Soils On Slope Failures

Jamalludin, Damanhuri (2016) Effect Of Shear Strength Parameters In Residual Soils On Slope Failures. ["eprint_fieldopt_thesis_type_phd" not defined] thesis, Universiti Sains Malaysia.

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Abstract

Faktor utama yang menyebabkan cerun runtuh di tanah baki adalah pengurangan kekuatan ricih akibat tanah menjadi tepu semasa musim hujan. Banyak cerun yang direkabentuk gagal dalam beberapa tempoh selepas ianya dibina. Oleh kerana kekuatan ricih sentiasa berubah-ubah, adalah perlu untuk kajian dibuat ke atas perubahan tersebut dan menentukan nilai batasan bawah untuk kegunaan merekabentuk cerun. Sampel tanah terganggu diambil dari cerun runtuh di Pulau Pinang dan Baling. Sejumlah 227 pasangan kejeliketan dan sudut geseran ricih berkesan diperolehi dari tanah cerun runtuh dan ianya diuji menggunakan ujian kotak ricih terkukuh salir dalam keadaan tanah terendam. Kedua-dua data kejeliketan dan sudut geseran berkesan diasingkan dan dibahagikan secara rawak kepada 2 kumpulan iaitu data model latihan 70%, dan data cerapan validasi 30%, menggunakan perisian Matlab. Dengan menggunakan ujian petunjuk prestasi ke atas 2 kumpulan data tersebut secara taburan jenis Normal, Weibull, Gamma dan Beta, didapati taburan Normal ialah taburan yang terbaik. Menggunakan nilai purata dan sisih piawai dari data model latihan, data ramalan validasi diwujudkan melalui perisian Matlab. Untuk tujuan validasi, dengan menggunakan ujian petunjuk prestasi, data cerapan validasi dibandingkan dengan data ramalan validasi. Di antara objektif utama penyelidikan ini adalah untuk menentukan nilai batasan bawah kekuatan ricih tanah yang diambil dari cerun runtuh. Dari taburan jenis Normal, nilai batasan bawah untuk c‟ = 0.86 kN/m2 dan ø‟=16.21o, nilai purata c‟ = 14.54 kN/m2 dan ø‟ = 31.31o manakala nilai batasan atas untuk c‟ = 44.88 kN/m2 dan ø‟ = 49.46o ditemui. Berdasarkan kepada statistik untuk taburan jenis Normal, adalah didapati bahawa hampir 95 % dari data berada diantara nilai batasan bawah dan nilai batasan atas dengan nilai purata berada ditengah-tengah taburan tersebut. Menggunakan perisian SLOPE / W berdasarkan keratan lintang cerun yang tidak gagal dan menggunakan nilai batasan bawah yang ditemui, adalah didapati nilai faktor keselamatan cerun adalah kurang dari 1. Ini mengesahkan bahawa nilai batasan bawah yang ditemui adalah betul. Nilai faktor keselamatan cerun adalah melebihi dari 1 apabila nilai purata dan nilai batasan atas digunakan ________________________________________________________________________________________________________________________ The main factor causing slope failures in residual soils is the reduction of shear strength parameters of the slope as the soil becomes saturated during the rainy seasons. Many engineered slopes failed some periods after their completion. Since the shear strength parameters of the residual soil are highly variable, there is a need to study their variability and thus determine the lower bound values to be used in the slope design. Disturbed soil samples were taken at the slope failures in Penang and Baling. A total of 227 pair of effective cohesion and fiction angle data were obtained from slope failures and tested under submerged condition using consolidated drained shear box tests. These effective cohesion and fiction angle were separated and both of them were divided randomly into 2 subset data namely model training data 70%, and observed validation data 30%, using the Matlab software. By conducting performance indicators on the 2 subset data using Normal, Weibull, Gamma and Beta distributions, Normal distribution was found to be the best fit distribution. Using the means and standard deviations of the model training data, predicted validation data were created using Matlab software. For validation purposes, performance indicators were conducted on both the observed and predicted validation data based on Normal distribution. Among the main objective of the research is to determine the lower bound values of the effective shear strength parameters of soils taken from slope failures. From the normal distribution curves of the model training data, the lower bound value of c‟ = 0.86kN/m2 and ø‟ = 16.21o, the mean value of c‟ = 14.54 kN/m2 and ø‟ = 31.31o while the upper bound value of c‟ = 44.88 kN/m2 and ø‟ = 49.46o were found. Based on the statistics of normal distribution, most the data of about 95 % will fall between the lower bound and upper bound values with the mean values in the middle. These lower values were tested using SLOPE / W software based on typical cross sections of un-failed slopes and the factor of safety was less than 1. This confirmed the lower bound values. The values of factor of safety were greater than 1 when the mean and upper bound values were used.

Item Type: Thesis (["eprint_fieldopt_thesis_type_phd" not defined])
Additional Information: Full text is available at http://irplus.eng.usm.my:8080/ir_plus/institutionalPublicationPublicView.action?institutionalItemId=3162
Subjects: T Technology
T Technology > TA Engineering (General). Civil engineering (General) > TA1-2040 Engineering (General). Civil engineering (General)
Divisions: Kampus Kejuruteraan (Engineering Campus) > Pusat Pengajian Kejuruteraan Awam (School of Civil Engineering) > Thesis
Depositing User: Mr Mohd Jasnizam Mohd Salleh
Date Deposited: 04 Sep 2018 08:47
Last Modified: 04 Sep 2018 08:47
URI: http://eprints.usm.my/id/eprint/41715

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