Suttisak Soralump

New and economical mixing method of cement-admixed clay for DMM application

Results of unconfined compression and one-dimensional compression tests of cement-admixed Bangkok clay confirmed the existence of an optimum mixing clay water content. That figure is defined as the total clay water content of the clay-cement paste that can give the highest possible improvement in strength of cured cement-admixed clay.Some related results of undefined compression tests of higher water content cement-admixed Ariake clay is also presented and discussed in the context of the existence of optimum mixing clay water content. Moreover, a concept supporting the possibility of the existence of optimum mixing clay water content in deep mixing applications has been explained, with a schematic diagram illustrating the effects of mixing clay water contents on the strength development of cement-admixed clay at a particular cement content. Significantly, at optimum mixing water contents, only 10 percent cement content by weight is needed instead of the corresponding 17 percent in conventional mixing methods, resulting in savings of 40 percent in cement content and cost.

Centrifuge Modeling of LNAPL Infiltration in Granular Soil with Containment

AbstractThis paper presents the results from four centrifuge experiments modeling light, nonaqueous phase liquid (LNAPL) migration in a sandy soil. These experiments were performed to evaluate the performance of a soil-cement wall used as a containment barrier and to investigate the effects of groundwater flow on LNAPL migration behavior. Centrifuge modeling experiments were performed at 30 g to simulate 80 days of LNAPL migration through the soil. Pore water pressure measurements and video recordings were used to evaluate the LNAPL migration behavior. Results show that in all tests, the water level was depressed because of the large volume of LNAPL confined between the walls. When groundwater flowed, the LNAPL migrated faster and deeper than when there was no groundwater flow. As a result, the depth of a soil-cement wall should be designed to a greater maximum depth to account for the groundwater-flow effects. In addition, numerical simulations were performed and validated with the centrifuge test result...

Cyclic Pore Water Pressure Generation and Stiffness Degradation in Compacted Clays

AbstractCyclic hollow cylinder torsional tests were performed in undrained conditions on 12 compacted clay specimens collected from two types of dams (an earth-core rock-filled dam and an earth-zone dam) in Thailand. The cyclic degradation, cyclic pore water pressure generation, and volumetric cyclic threshold shear strain were studied via multistage strain-controlled tests. The testing program encompassed five overconsolidation ratios (OCRs), 1, 1.5, 2, 3.5, and 4, where six to eight cyclic strain-controlled stages were applied in each test with frequency f=2  Hz. The results reveal that the volumetric threshold shear strain amplitude of these compacted clays ranged between approximately 0.009 and 0.025% and generally increased substantially with the plasticity index (PI). The cyclic pore water pressures normalized by σc′ are consistently lower than previous ones using other types of clays tested with other types of devices at comparable cyclic shear strain amplitudes. The cyclic degradation and cyclic p...

Local Site Investigation of Liquefied Soils Caused by Earthquake in Northern Thailand

ABSTRACT Ambient noise measurements and spectral analysis of surface waves were performed in Mae Lao to investigate the local site effects of the May 5, 2014 Mae Lao earthquake in Northern Thailand. Site investigations were conducted to determine horizontal to vertical spectral ratio, predominant frequency, and shear wave velocity profile. The results showed that the liquefied locations were classified as Site Class D. The low Vs profile at the shallow depth confirmed evidences of liquefaction in this area. The results could bring an understanding of site response and dynamic behavior of soils during earthquake in the Northern Thailand.

Penetration behavior of chemical grouting considering ground uncertainty

The chemical grouting is one type of ground-improvement methods. It injects liquid consolidation material into the gaps of a soft sandy ground. It is mainly used for improving a stable ground, such as by preventing liquefaction and increasing the strength of the ground. Chemical grouting has been successfully applied at many construction sites; however, the behavior of the chemical solution being injected into the ground is unclear. Furthermore, because the ground involves uncertainty, it is difficult to determine the penetration range of the chemicals (grouting materials). In this study, the authors carry out a seepage flow analysis of a chemical solution for a ground requiring improvement due to uncertainty. They then compare the difference in the behavior of the chemical solution between the case in which the ground is assumed to be heterogeneous and that in which it is assumed to be homogeneous.

Assessment of potassium silicate based surface penetration materials with low viscosity in the repair of concrete structures

In recent years, surface penetration has attracted attention as a repair method for concretes structures. Silicate based penetration materials have been used in this method. In this study, visual appearance, water permeability, water absorption, water-vapor permeability, neutralization (carbonation) and chloride ion penetration testing of a silicate based surface penetration material are performed. The protection and waterproofing effects of a silicate based surface penetration material are evaluated based on the results. The silicate based surface penetration material penetrates deeply into the concrete surface, shows self-repair functionality, is effective to the neutralization (the carbonation) of the concrete and improves the performance of waterproofing. The penetration depth of the silicate based surface penetration materials plays an important role in the surface penetration method. Therefore, permeability testing of a mortar specimen, penetration depth testing of the mortar specimens with various silicate based surface penetration materials, viscosity testing of the materials and modelling of the one dimensional penetration into the mortar specimens are performed. The results of viscosity testing and coefficient of permeability suggest that these silicate based surface penetration materials will perform well surface penetration materials.

Life cycle assessment on recycling of construction sludges in geotechnical engineering fields

Although waste recycling has been promoted in response to increasing environmental awareness in Japan, its marketability is being questioned due to the recycling cost. The ultimate goal of waste recycling is to reduce the environmental load. In this paper, we examined the evaluation method for social environmental efficiency to socially evaluate waste recycling, by incorporating environmental load as an environmental cost in addition to the direct cost. The social environmental efficiency evaluation including consideration of uncertainties is conducted, because waste recycling involves various uncertain elements. As the results, the social environmental significance of construction sludge recycling can be evaluated quantitatively while focusing on the particular construction sludge with a lower recycling rate.

Effect of the molar ratio of liquid glass grouting agents on mechanical characteristics of the solidified soils

Chemical grouting techniques are used as ground improvement methods to obtain stable ground. In this method, soft sandy soils are solidified by injecting liquid solidification agents into the soils to prevent liquefaction as well as to increase strength. In this study, liquid glass grouting agents containing liquid glass with a higher polymerization degree (No. 5 liquid glass grouting agents) are being developed and discussed while focusing on the liquid agents to be used for chemical grouting techniques. Specifically, the solidification properties of No. 5 liquid glass grouting agents and the influence of the molar ratio of liquid glass to the strength and shrinkage characteristics of sand-gel and homo-gel are experimentally studied. As a result, the sand-gel made of No. 5 liquid glass grouting agents is superior in strength and has smaller shrinkage ratios after gelation, and therefore, is superior in soil improvement.

Influence of Kaolin Mixture on Unsaturated Shear Strength of Decomposed Granitic Silty Sand

The paper reports on the influence of kaolin content on shear strength of a decomposed granitic silty sand. The granitic soil was mixed with kaolin, with the purpose of erosion protection and slope stabilization. Shear strength and water retention behaviour of the decomposed granitic silty sand, mixed with different proportions of kaolin (from zero up to 20% by weight) were tested. A tensiometer was also incorporated in a direct shear box to investigate unsaturated properties. The silty sand mixed with 10% kaolin possesses the highest saturated shear strength. The effective cohesion increases with increasing kaolin content, while the effective friction angle reaches the maximum value at the 10% kaolin. In the unsaturated condition, the angle of shear resistance with respect to suction increases with kaolin content. Based on the test results and field observation, the silty sand mixed with 10% kaolin appears to be most erosion-resistant.