Several studies have been carried out on engineering geology and geotechnical properties of TEHRAN ALLUVIUM with emphasis on cementation, cohesion, strength, etc. However, there are few studies with focus on excavation stability and pattern. This paper focuses on excavation pattern of fine grained ALLUVIUM in SOUTHern TEHRAN. Thus, physical and mechanical properties of soil were determined from field investigation and laboratory tests. Afterward, stability analyses were performed using GeoStudio software with Morgenstern-price method based on limit equilibrium. According to the results, the studied region was divided into three zones: D 1, D2 and D3 based on excavation stability pattern. Because of low presence of sand in D 1 zone, safe excavation depth is more than the others. The excavation depth of vertical wall in D2 and D3 zones is the same, but in deeper excavations in both zones, D3 zone showed more instability.

The results of over 100 geotechnical site investigations in different zones of TEHRAN ALLUVIUM in the SOUTH part of TEHRAN city were analyzed to determine the correlation of modulus between elasticity and SPT number of soil in SOUTHern TEHRAN ALLUVIUM. The alluvial deposits in SOUTHern TEHRAN are composed mostly of fine-grained materials or coarse-grained soils with silt and clay particles. Based on the soil material properties, the study area is divided into three sections. In each section, the results of a large number of in situ and laboratory tests are classified and analyzed to determine the elastic modulus of soil. The study shows that, for the first part of the area the modulus of elasticity from plate load test correlates well with SPT number and for the second and third parts, the direct shear and triaxial tests have an acceptable correlation with SPT number. Formulas relating elastic modulus to standard penetration test number are given and compared to those reported in the literature. Also, from the analysis of data it was seen that the elastic modulus of soil is increased with increase of maximum soil particles. Finally average results for unconfined strengths of fine grained soil in ALLUVIUM of the SOUTH of TEHRAN are presented.

The coarse-grained ALLUVIUM of TEHRAN area has undergone cementation processes through the time that notably affects its strength. The rate of cementation is influenced by many factors including original texture, type and shape of grains, geological history, ground water conditions, tectonically pressures, depth and weathering processes. The main geotechnical features of the ALLUVIUM such as strength, stiffness, bearing capacity, and stability of slopes and underground excavation is directly related to the degree of cementation of this deposit.This paper reviews the process of cementation of TEHRAN's alluvial deposit and considers the effect of cementation on the mechanical behaviour of the deposit. Cementing material of TEHRAN ALLUVIUM predominantly was deposited by groundwater. The composition of the cement material is carbonated and is mainly consisted of calcite. The original texture and gradation of the soil has a considerable effect on cementation process and strength. When the content of fine materials is less than about 15%. The cement material bonds directly the coarse grain particles. On the other hand, When the content of fine grains exceeds 15%, the contacts between coarse particles is dominantly by that material, so the strength of deposit is mainly affected by fine materials. The results of in-situ and laboratory tests show that the cementation increases the strength and stiffness of soil, and changes the ductile behaviour of soil to brittle during shear. Moreover, the cementation increases the failure envelope curvature.  

The proposed classification based on the combination of geological variables and geotechnical parameters provides the possibility of using geological knowledge in estimating the geotechnical parameters. The city of TEHRAN is one of the metropolises that founded on Quaternary ALLUVIUM. The ALLUVIUM is divided into four groups, A, B, C, and D, based on age and formation conditions. Some researchers have proposed a new classification using the combination of geological variables and geotechnical parameters for A and C TEHRAN's alluvia. The aim of this study is to sub-classification of unit B of TEHRAN alluvia based on combination of geological variables and geotechnical parameters. In this research, based on geological findings in 66 locations of TEHRAN's alluvia, the geological variables affecting the geotechnical parameters of the coarse-grained B alluvia including grain size, grain form, grain contact, cement between grain, homogeneity and layering were identified and based on these variables, unit B was divided into four units of Bn1, Bn2, Bn3 and Bn4. Using the results of 27 performed direct shear test and 70 plate loading tests in specified units, the geotechnical parameters of these four units, including the internal friction angle, cohesion, and modulus of deformability were determined. With combination of geological variables and geotechnical parameters, new classification of unite B was proposed that make it is possible to estimate the geotechnical parameters based on the geological variables for this ALLUVIUM.

City of TEHRAN is founded on Quaternary ALLUVIUM. During the last years, several researchers have studied characteristics of this ALLUVIUM. Amongst them, Rieben classification has been the most widely used classification rather than others. Rieben (1955) divided TEHRAN ALLUVIUM to four categories, A, B, C and D which are ranged from old to young, respectively, in terms of geologic age. In Rieben study, age and general characteristics of ALLUVIUMs are considered rather than geotechnical and engineering applications. Study of ALLUVIUM based on age can give useful information about history of basin sedimentation and relevant change's trends and even it may help geotechnical engineers for preparing study plan and making sound conclusions over undertaken studies. For doing so, it is required to evaluate ALLUVIUM classifications with respect to sedimentation types. In order to evaluate Rieben classification capabilities for geotechnical studies of TEHRAN ALLUVIUM, following subjects are studied in this research: (A) Description of Rieben and other classifications that are presented based on age and specification of geology. (B) Discussing advantages and disadvantages of existing classifications in geotechnical studies. (C) Analysis of TEHRAN geological maps with consideration of ALLUVIUM formation and making comparison of these maps with some boreholes, test pits and site visit results. (D) Discussing geological factors affecting on geotechnical specifications of TEHRAN ALLUVIUM.

Earth slopes and high vertical cuts are frequently observed to be stable for long period in the coarse-grained soils of TEHRAN. Their stability is often attributed to cementation effects that produce improved shear strength parameters. These soils are heterogeneous not only in gradation and density but also in cementation. Due to this heterogeneity and the extreme difficulty in obtaining undisturbed samples, artificially cemented specimens using lime as the cementing agent are used to understand the effects of cementation on the shear strength parameters. A base soil with 45% gravel, 49% sand and 6% fine material was used, based on gradation curves of the coarse-grained soils of TEHRAN. Specimens with 100mm diameter and 200mm height are prepared by mixing of the soil with 1.5, 3, and 4.5 percent by weight lime and after curing weretested using drained triaxial compression tests. Samples were also tested in uncemented and destructured conditions. The results of the tests indicate that the cementation increases peak shear strength, suggesting an increase in cohesion. Cemented samples show a brittle failure mode at low confining pressure with a transition to a ductile failure mode at higher confining pressures. The stress-strain curves for cemented samples show a clear peak stress followed by a sudden drop in stress and strain softening. There is no clear peak in shear stress for uncemented and destructured samples. The failure envelope is curved for cemented samples. The influence of cementation on the friction angle of the tested samples is a function of confining pressure, and degree of cementation. The results show that the peak friction angle at low confining pressure increases with increase in cementation. The residualfriction angle is almost equal for cemented, destructured and uncemented samples.

The most parts of TEHRAN area has been covered by coarse-grained ALLUVIUM deposits. So far, it has been difficult to obtain accurate strength and deformation parameters of the ALLUVIUMs using laboratory and conventional in-situ tests.The presented paper explains the problems exist on using Menard pressuremeter in TEHRAN coarse-grained ALLUVIUMs, from execution point of view including the preparation of test pocket and operation, and proposes the adequate method. In addition the paper studies the shear moduli of this soils, obtained from Menard pressuremeter, plate loading and shear wave tests.The studies show that the shear moduli of cemented ALLUVIUM is, in average, 1.7 to 2 times greater than uncemented one.Also, the shear moduli increase with depth of tests, and the rate of increase is more rapid for cemented one than uncemented. However, because of strain level dependency of shear modulus, the shear moduli obtained from pressure meter are smaller than plate loading and very smaller than shear wave moduli. The stress-strain behaviour of TEHRAN ALLUVIUM soils, as expected, is non- linear.

In the present study, the main purpose is the qualitative study on garbage collection in TEHRAN city. It has been done by qualitative research method. Semi-structured interview and purposeful sampling techniques were used in data collection. To do this, 15 people were interviewed and the sample size in the present study was determined based on theoretical saturation. Thematic analysis was used to analyze the data. Theme analysis was performed at 4 levels of primary, main, central and core themes. A total of 184 initial themes were extracted from all interviews. In the main coding stage, the following 9 main themes were merged. Escape from poverty in the origin and the inevitable choice of inferiority, society's view to garbage collectors, and high stress, strengthening the cycle of academic reluctance and illiteracy, physical and mental torment, unknown horizon and confusion of the Khojies, legal ambiguity and customary definitions and contracts, complaints from relevant institutions, the entry of the mafia and the formation of rent and corruption. Finally, these themes fall into two categories of social harmfulness of recycling and institutional exclusion and illegallity of the status of garbage collectors in the second distrect in the form of the core theme of the structure of socially harmful and institutionally illegal, waste phenomenon explained..

In the present study seismic data was carried out at Bibi -Shahr Banoo mountainous area located in Shar-e-Ray SOUTH-east of TEHRAN to estimate amplification of seismic waves. For this purpose microtremors and explosion generated waves were acquired. The layout of three recording stations was arranged along a profile. Microtremors were recorded after midnight with time interval of 30 minutes; record length for each interval was 2 minutes. Explosion charges were about 120 kg of dynamite, and 850 kg of amfo. Three Protable Data Acquisition System (PDAS 100) recording stations along a profile with interval of 50 to 150 meters were deployed to record the seismic waves. Data was processed using Digital Signal Processing (DSP) software. Then the classical Spectrum ratio and Nakamura"s ratio methods have been evaluated. It should be noted that, all obtained results are reliable in frequency range of 0 to 10 Hertz. The obtained results were classified in four stages as follows: Microtremors: obtained amplification factor, in average, from two recording stations using Nakamura's ratio method shows greater values than that of obtained from classic reference station method. The obtained results for the used methods are summerised as the following; Explosion: The above result was obtained the same, while explosion was used as a source. Nakamura's method: In comparison between microtremors and explosion generated waves, the Nakamura's method, in average resulted greater amplification factor while explosion was used as a source. Classic reference station method: In comparison between microtremors and explosion, classic reference station method, in average resulted greater amplification factor while explosion was used as a source.

Preparation of Iso-Velocity and Iso-Depth maps for different shear wave velocities in TEHRANs ALLUVIUM is the main subject of this paper. In this regard, data obtained through geoseismic and geotechnical investigations was used. The collected geotechnical data of about 1000 boreholes including results of 26 new drilled boreholes are considered and combined with the results of 95 refraction surveys and 9 down hole surveys in the studied area. Furthermore the combination of geoseismic surveys, collected geotechnical data and in-situ measurements in drilled boreholes are used to propose a new classification of TEHRANs soils based on shear wave velocity and N(SPT). A comparison also is made between results of Standard Penetration Test (SPT) in drilled boreholes and shear wave velocities obtained from geoseismic surveys. The new correlations established between N (SPT) and shear wave velocity for different types of fine-grained soils in SOUTH of TEHRAN are proposed.