In-Situ Assessment of Linear and Nonlinear Dynamic Properties of Municipal Solid Waste.

Dynamic properties of solid waste are critical to reliably evaluate the seismic response of landfills. In this study, the dynamic properties of solid waste including shear wave velocity (Vs), small-strain shear modulus (Gmax), and normalized shear modulus (G/Gmax) reduction curve, were investigated in situ. Semi-empirical and empirical models for the Vs of municipal solid waste (MSW) were developed. The semi-empirical model is a more comprehensive model that aims to separately capture the effect of waste density and confining stress on the shear wave velocity of MSW. It was formulated using data generated from large-scale laboratory studies on reconstituted MSW. The empirical model has a simpler mathematical expression that is a function of depth only. The parameters of both models were derived by calibrating them against a total of 49 shear wave velocity profiles, including 13 Vs profiles that were generated in this study. The models can be used to estimate the Vs of MSW and to evaluate the seismic response of landfills. A field testing method to investigate the dynamic properties of solid waste was implemented in four landfills using the George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES) facilities. Field investigations were performed at three MSW landfills, namely Austin Community Landfill (Texas), Lamb Canyon Sanitary Landfill (California), and Los Reales Landfill (Arizona). Field investigation was also conducted in a class I hazardous landfill, namely BKK Landfill. The field method was primarily aimed at evaluating shear wave and primary wave velocities as well as, for the first time, the shear modulus reduction curve of solid waste. The relationship between shear modulus and shearing strain was investigated by applying dynamic horizontal loads at the waste surface in a staged-loading sequence generated by a NEES mobile field shaker. The solid waste response was measured with buried arrays of three-component geophones. The testing method also allowed an assessment of the effect of confining stress and waste variability on the dynamic properties of solid waste. A model for normalized shear modulus reduction curves of solid waste was recommended based on field testing results.PHDCivil EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/108994/1/sahadewa_1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/108994/2/sahadewa_2.pd

Strength and Deformation Characteristics of Reconstituted Sand under Different Stress Paths in True Triaxial Tests

To improve the geotechnical stress"“strain analysis, the stress"“strain behavior of geomaterial under general three-dimensional stress conditions prevailing in the field need to be captured. The true triaxial apparatus is an enhanced version of the conventional triaxial apparatus, which allows to simulate stresses by applying loadings independently in 3 orthogonal directions. This study evaluated the strength and deformation behavior of Bangka sand under true triaxial test conditions. The test specimens were prepared by means of the multi-sieve sand pluviation method. Various true triaxial test stress paths were applied under axial compression, lateral extension, axial extension, and lateral compression with the objective of understanding and developing the empirical correlation of coarse-grained soil strength parameters in axial compression stress paths related to other stress paths. The test results showed that an increase in the value of b, the parameter used to quantify the relative magnitude of the intermediate principal stress to the other principal stresses, resulted in an increase of the internal friction angle and a decrease of the peak stress ratio. In addition it was observed that the Lade-Duncan failure criterion fitted the results of this study better than other failure criteria, namely the extended von Mises, Mohr-Coulomb, and Matsuoka-Nakai failure criteria

Parametric Study of One-Dimensional Seismic Site Response Analyses Based on Local Soil Condition of Jakarta

Seismic site response analysis is used to estimate the response of soil deposits during seismic loading at any depth of interest and to interpret time histories as well as response spectra. This type of analysis involves many parameters that can affect the character of ground shaking. It is important to know the effect of these parameters in order to perform reliable seismic hazard evaluation at a site. This paper presents the effects of several parameters toward the characteristics of surface response spectra based on the local soil conditions of Jakarta using a one-dimensional (1-D) site response model with total stress approach. A parametric study was performed on two cohesive soil deposit profiles with a different site class, namely medium clay (site SD) and soft clay (site SE). The bedrock layers of both profiles were located at a depth of 300 m. In this study, the analytical methods implemented were the equivalent-linear method and the non-linear method. Several different dynamics soil models were also implemented. In addition, variation of property parameters, such as depth of bedrock, shear wave velocity of bedrock, layer thickness, etc., were studied. The results of this study indicate that all of the studied parameters have a significant effect on the response spectra at the ground surface

An Evaluation of Pile-Raft Interaction in Cohesive Soils using 3D Finite Element Method

This paper presents the results of a numerical study of soil-structure interaction in a piled-raft foundation system in clay soil by reviewing the deformation and load transfer mechanism of the piled-raft foundation system. ABAQUS was used to evaluate the interaction in the system, while a Mohr-Coulomb constitutive model was chosen to model the clay soil. Verification of the model was conducted by comparing the simulation result to an experimental laboratory result. The verification result showed that the model used in this research agreed well with the experimental laboratory research. Subsequently, a parametric study was performed by varying the pile spacing, raft size, pile length, and raft thickness. A parametric study was conducted on very stiff and hard clays. This study concludes that the load transfer mechanism in a piled-raft foundation system between the pile and raft foundation occurs after the pile reaches its ultimate capacity and is in the plastic zone

Pengaruh Strength Reduction Tanah Clay-Shale Akibat Pelaksanaan Pemboran Terhadap Nilai Daya Dukung Pondasi Tiang Di Jembatan Suramadu Berdasarkan Analisis Hasil Tes OC

. Suramadu Bridge, which will connect Surabaya and Madura, is designed to have 5,438 m total span. Considering bridge construction that is above sea and huge design load on its pile foundations, conventional static loading test can not be performed at the main bridge. Alternative pile load test that can be performed is OC Test, which followed Osterberg Cell Test procedure. Equipped with load cell, telltale, and strain gauge, this test can provide load-displacement curve of end bearing and skin friction at any depth. Soil investigation result shows existence of clay-shale layer, which contains montmorillonite, at bore pile's location. This soil is sensitive to lateral pressure reduction caused by boring and weathering process so that strength reduction can occur. Strength reduction of soil makes end bearing and skin friction difficult to be predicted. Strength reduction effect toward end bearing and skin friction are determined by means of comparing OC Test result to prediction result based on common empirical correlation. For end bearing, OC Test result shows value that close to prediction result's. Therefore, strength reduction of end bearing caused by boring is relative small. On the other hand, skin friction measurement result shows that its value is much smaller than prediction result's. For increasing bearing capacity, grouting through the pile base was conducted. Test result shows increasing of value either end bearing and skin friction after grouting through the pile base. Compared to end bearing's value, skin friction's value rise more and close to prediction value

Parametric Study of One-Dimensional Seismic Site Response Analyses Based on Local Soil Condition of Jakarta

Seismic site response analysis is used to estimate the response of soil deposits during seismic loading at any depth of interest and to interpret time histories as well as response spectra. This type of analysis involves many parameters that can affect the character of ground shaking. It is important to know the effect of these parameters in order to perform reliable seismic hazard evaluation at a site. This paper presents the effects of several parameters toward the characteristics of surface response spectra based on the local soil conditions of Jakarta using a one-dimensional (1-D) site response model with total stress approach. A parametric study was performed on two cohesive soil deposit profiles with a different site class, namely medium clay (site SD) and soft clay (site SE). The bedrock layers of both profiles were located at a depth of 300 m. In this study, the analytical methods implemented were the equivalent-linear method and the non-linear method. Several different dynamics soil models were also implemented. In addition, variation of property parameters, such as depth of bedrock, shear wave velocity of bedrock, layer thickness, etc., were studied. The results of this study indicate that all of the studied parameters have a significant effect on the response spectra at the ground surface

Pengaruh Strength Reduction Tanah Clay-Shale Akibat Pelaksanaan Pemboran Terhadap Nilai Daya Dukung Pondasi Tiang di Jembatan Suramadu Berdasarkan Analisis Hasil Tes OC

Abstrak. Jembatan Suramadu yang akan menghubungkan kota Surabaya dengan Madura memiliki bentang total sepanjang 5.438 m. Mengingat lokasi pembangunan yang berada di laut dan beban rencana yang besar pada tiang pondasi, maka uji pembebanan statik konvensional tidak mungkin untuk dilakukan di jembatan utama. Alternatif tes pembebanan tiang yang dapat dilakukan adalah Tes OC yang mengikuti  prosedur Osterberg Cell Test. Tes ini dilengkapi dengan load cell, telltale, dan strain gauge sehingga dapat diperoleh kurva load-displacement untuk tahanan ujung dan tahanan selimut pada berbagai kedalaman. Hasil penyelidikan tanah menunjukkan keberadaan lapisan tanah clay-shale yang mengandung montmorillonite pada lokasi tiang bor. Jenis tanah ini sensitif terhadap berkurangnya tegangan lateral akibat pemboran dan terhadap weathering process sehingga dapat terjadi strength reduction. Strength reduction tanah menyulitkan predikasi tahanan ujung dan tahanan selimut pondasi tiang bor. Hasil Tes OC digunakan sebagai acuan dalam menentukan pengaruh strength reduction terhadap tahanan ujung dan tahanan selimut dengan cara membandingkan hasil pengukuran dengan hasil prediksi berdasarkan korelasi empiris yang umum dipakai. Untuk tahanan ujung, hasil Tes OC menunjukkan harga yang relatif dekat dengan hasil prediksi sehingga strength reduction untuk tahanan ujung akibat pemboran relatif kecil selama kondisi dasar pondasi bersih. Sedangkan untuk tahanan selimut, hasil pengukuran nilainya jauh lebih kecil dibanding hasil prediksi. Untuk meningkatkan daya dukung, maka dilakukan grouting melalui ujung tiang. Hasil pengujian menunjukkan bahwa setelah dilakukan grouting pada pondasi terjadi kenaikan nilai tahanan ujung dan tahanan selimut. Dibandingkan dengan tahanan ujung, tahanan selimut memiliki peningkatan kekuatan yang lebih besar dan setelah dilakukan grouting nilainya mendekati nilai prediksi. Abstract. Suramadu Bridge, which will connect Surabaya and Madura, is designed to have 5,438 m total span. Considering bridge construction that is above sea and huge design load on its pile foundations, conventional static loading test can not be performed at the main bridge. Alternative pile load test that can be performed is OC Test, which followed Osterberg Cell Test procedure. Equipped with load cell, telltale, and strain gauge, this test can provide load-displacement curve of end bearing and skin friction at any depth. Soil investigation result shows existence of clay-shale layer, which contains montmorillonite, at bore pile's location. This soil is sensitive to lateral pressure reduction caused by boring and weathering process so that strength reduction can occur. Strength reduction of soil makes end bearing and skin friction difficult to be predicted. Strength reduction effect toward end bearing and skin friction are determined by means of comparing OC Test result to prediction result based on common empirical correlation. For end bearing, OC Test result shows value that close to prediction result's. Therefore, strength reduction of end bearing caused by boring is relative small. On the other hand, skin friction measurement result shows that its value is much smaller than prediction result's. For increasing bearing capacity, grouting through the pile base was conducted. Test result shows increasing of value either end bearing and skin friction after grouting through the pile base. Compared to end bearing's value, skin friction's value rise more and close to prediction value