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Slope Stability by Soil Nailing for Road Widening in Hikawa Tunnel, Tokyo, Japan
Nakazawa J.
The described project involved a two-lane road with many curves in a mountainous area of Tokyo. The purpose of this project was to make the road straight for overcoming the problem of heavy traffic. As one of the measures, in the year 1985, it was decided to construct a road tunnel in the hilly part. For connecting the existing road at one exit of the new tunnel, the road had to be widened by cutting the slope. The cutting slope was stabilized by soil nailing, which was a combination of rebar with 80–100 mm diameter and cast-in-place mortar placed in the drilling hole.
Cement Deep Mixing for Levee Repair in Louisiana, USA
Kafle S., Griffin R.
Cement deep mixing (CDM) was selected as a ground improvement technology and designed to treat the soft ground of a 2224 m long section of levee along the west bank of the Mississippi River for emergency repair. The project owned by the United States Army Corps of Engineers (USACE) was a part of the Louisiana Hurricane Protection Project. A series of overlapping CDM columns (panels) oriented in the transverse direction of the levee was installed. The primary purpose of these panels was to provide shear resistance to the levee against lateral loads at high flood water conditions. In addition, these panels were designed to support the additional vertical load generated by the increased height of the levee and to control the long-term settlement of the remediated levee, which might otherwise occur due to the compression of the soft foundation soils. A total of 41,500 m3 of CDM was produced.
Epilogue
Hazarika H., Nakazawa J., Nakahara I.
The case histories described in this book include examples from both developing and developed countries. The purpose of selecting these case histories was to let the younger generation of engineers and researchers learn from these examples. Those knowledges can help them in selecting a particular ground improvement technique that best suits the varying geology, budget constraints, and available technologies, depending on the countries.
Ground Freezing for Shield Tunneling, Japan
Tsuchiya T.
The ground freezing method is a ground improvement technique used as temporary work such as in shield tunnel construction. This chapter introduces two projects using the ground freezing method in Japan. One is a case adopted to remove the existing steel sheet piles under the subway tunnel structure; the other is a case adopted as shield arrival protection work of a discharge tunnel in the thermal power plant station. In the former case, it was necessary to excavate an adit under the existing subway tunnel structure in order to remove the existing steel sheet pile. The ground freezing method was adopted as a protection work for excavation of the adit. In the latter case, a newly developed CO2 ground freezing method was adopted for the first time in the world, in order to cut off water at arrival point of the shield to build discharge tunnels. The ground freezing method of the CO2 has advantages such as lower temperatures and smaller freezing facilities as compared with the conventional method, in addition to reducing environmental loads. In this case, the construction period was shortened utilizing the advantage of CO2 system.
Combined Ground Improvement Method for Cultural Heritage Preservation—A Case Study in Angkor Ruins, Cambodia
Akazawa Y., Fukuda M., Iwasaki Y., Nakazawa J.
The historical ruins, which consisted of rocks or soils, are treated for their preservation. In many cases, the ground improvement techniques are being used for the preservation of them. One tower of Angkor ruins was deemed as the most dangerous tower among them for restoration work. The compacted sandy formation was found from −1.5 m from the original ground surface and to +3.5 m above the ground. The safety factor for the ground bearing capacity in rainy season was calculated with S.F = 1.1. When its bearing strata were reconstituted, it was designed to have a sufficient safety factor value of S.F > 1.5. To achieve this purpose, the original sandy soils were mixed with slaked lime and compacted by tamping with geotextile. The material soil used for the platform was a mixture of different soils of original sandy soil, clayey soil, and lateritic soil at weight ratios of 70, 15, and 15%. Slaked lime was added to the mixed soil 1 at a rate of 0.1.
Reinforcement of Runway Embankment by Using Geosynthetics in Sulawesi, Indonesia
Gouw T.
Being a country of 17.504 islands, Indonesia needs a lot of airports in reaching out to its remote islands to provide people and goods mobility. Some of these airports have to be built on hilly terrains which require massive cut and fill operations resulting in high man-made slopes. Very often some sort of reinforcement is required to build a stable high slope. Considering Indonesia lies in a high seismicity area, the flexible nature of geosynthetic reinforced soil structures or mechanically stabilized earth walls is preferable to rigid concrete retaining wall system. This article elaborates on the challenging geotechnical problems of building 15–37 m high slopes on clay shale formation. It discusses the strength degradation of the clay shale, the design aspects, and the construction process of the geosynthetic reinforced soil slopes.
Applications of Waste Tires for Protection of Embankments in Northern and Northeastern Japan
Hazarika H., Kuribayashi K., Kuroda S., Yasuhara K., Karmokar A.K.
This chapter deals with two case studies in which waste tires were used to protect embankments. The first one is related to a series of forensic and laboratory investigations of an existing retain wall made of tires, which did not suffer any damage neither by earthquake nor by tsunami during the 2011 Off the Pacific Coast of Tohoku Earthquake, Japan. The second one is related to the field trial and laboratory investigation on the use of tire shreds, a granular material derived from waste tires, to enhance the drainage in a highway embankment.
Ground Improvement Using Prefabricated Vertical Drains with Preloading for Port Park Area at Chittagong, Bangladesh
Siddique A., Dhar A.S., Ameen S.F.
A container yard was constructed for handling of loaded containers at Port Park area of Chittagong Sea Port in Bangladesh covering an area of 60,700 m2 (15 acres). The sub-soil within the yard contained layers of very soft to soft strata of clayey silt/silty clay at depths of 1.0–3.5 m below the existing ground level. Ground improvement using prefabricated vertical drains with preloading was undertaken to pre-consolidate the sub-soils. The maximum settlements measured during the field monitoring period varied from 220 to 415 mm and the settlements were almost completed after 30–52 days of preloading. Predictions with and without considering smear effects had shown to provide an upper bound and lower bound of the consolidation time, respectively.
Log Piling Method for Liquefaction Mitigation and Carbon Stock in Large Residential Area, Chiba, Japan
Numata A., Matsushita K.
Because using wood helps mitigate global warming by storing carbon, the log piling method for liquefaction mitigation and carbon stock (known as the LP-LiC method) have been developed. To mitigate the liquefaction potential, a large area (approximately 13,400 m2) of residential ground in Chiba, Japan was improved with LP-LiC. Much liquefaction occurred in the area surrounding this site during the 2011 Great East Japan Earthquake. Because the site is located in a residential area, the improvement method must involve low vibration, low noise, no surplus soil, and no displacement of the surrounding area. For these reasons, LP-LiC was adopted for the site. The method ultimately stored approximately 790 t-CO2 at this site while improving the ground.
Introduction
Hazarika H.
In this chapter, a brief introduction of the 12 case studies covered in this book is given. The case studies discussed here belong to each category of ground improvement techniques described in the book “Essentials of Ground Improvement Techniques” by Hazarika et al. (Essentials of ground improvement techniques, Springer Nature, [2]).
Use of Coir Geotextiles in Erosion Control, South-West India
Balan K., Jayasree P.K., Devaraj C.R.
Geotextiles with natural fibers like coir, jute, sisal, hemp, etc. are used in many non-critical civil engineering applications like erosion control. The main advantage of geotextiles with natural fibers is that they are ecofriendly and biodegradable. They can be successfully used in limited life applications of geotechnical engineering. This paper deals with some case histories on the use of woven and stitched non-woven coir blankets for erosion control and slope stabilization, executed by the authors.
Full-Scale Embankment in Soft Bangkok Clay Using Jet Grouted Cement Mixing Piles
Bergado D.T., Chaiyaput S., Jamsawang P.
A full-scale test embankment reinforced with hexagonal wire mesh was constructed and monitored to evaluate its performance. The embankment was constructed with precast vertical discreet concrete panel as facing element and silty sand was selected as granular backfill material. The size of each concrete facing panel is 1.5 m × 1.5 m × 0.15 m. The embankment was founded on soft Bangkok clay reinforced by columnar inclusions. Jet grouting method was used to construct the clay-cement piles to improve the soft foundation ground. The objectives were to study and confirm the behavior of the hexagonal wire mesh reinforced embankment constructed on jet grouted cement mixing piles to improve soft ground. The observed data with analytical calculation and finite element analysis were compared in terms of surface settlements, subsurface settlements, lateral movement, excess pore pressure, and tension in hexagonal wire mesh. The analytical prediction of the surface settlements and the FEM simulation of the test embankment deformation behavior yielded good agreement with the corresponding observed data.
Soil–Cement Method for Jobsite Road Foundation Ground Construction—Using “Moist Cement”
Wakahara C., Furuse T.
The construction project of Tokai-loop Expressway, which connected many cities in and around Nagoya, Japan was planned. Since the elevated type expressway was adopted for this project, many jobsite roads were needed for carrying out the operation of construction machines. By adopting soil–cement, the traffic-ability of the soft ground can be improved and the surplus soils from jobsites can be utilized effectively. Considering solidifying materials and their effects, the construct-ability and the economic benefits, etc., soil–cement by “Moist Cement” was adopted.
Application Examples of the Sand Compaction Pile Method in the United States
Harada K., Nozu M., Matsushita K., Imai Y.
The Sand Compaction Pile (SCP) method is a typical soft ground improvement method in Japan and has been widely used as a liquefaction countermeasure. The type of SCP method that has been conventionally available is a vibratory one using a vibration hammer. Currently, a non-vibratory type mounted with a forced lifting/driving device—the non-vibratory SCP method—has been developed so as to be applicable to the construction in urban areas. This paper introduces an example of applying the non-vibratory SCP method to the construction of a levee in California in the United States. In the construction, the non-vibratory SCP method was applied to the ground improvement as a measure to prevent lateral spreading of the ground due to liquefaction. In addition to the on-site confirmation of the vibration reduction and ground improvement effects of the non-vibratory SCP method during the construction, this paper additionally discusses the ground improvement effect in terms of liquefaction and settlement prevention.
Significance of Drainage Measures on Landslide Mitigation Measures
Korulla M.
Landslide prevention is a function of decrease in the driving forces or an increase in the resisting forces. Any landslide mitigation measure used must have one or both of the above parameters. Improper drainage is the most important single contributor to landslide initiation. Adequate drainage of water is the most significant element of landslide mitigation measure for both existing and potential landslides. Drainage can be either surface (roadside drains, catch/interceptor drains and chute drains) or subsurface (drainage pipes or horizontal drains, internal drains of retaining soil structures, etc.) measures. This paper briefly mentions about different types of drainage systems and various drainage schemes proposed at few locations along National Highway 58 at Uttarakhand as a part of landslide mitigation measure.
Ground Modification Techniques to Improve Liquefaction Resistance in Indo-Gangetic Soils
Shahu J.T., Mohanty M.
Liquefaction is a well-known seismic hazard during which soil starts behaving like a fluid and is no longer be able to support structure due to the reduction in its shear strength. Deep ground modification techniques can be very effective in reducing liquefaction potential by vibration/displacement/stabilization of loose granular soil. In this paper, the efficacy in mitigating the liquefaction potential of soil by different methods of ground improvement, by comparing SPT and eCPT values of the soil before and after the soil improvement, are discussed.
Design of Waterfront-Retaining Walls Subjected to Waves and Earthquakes: A Review
Choudhury D., Rajesh B.G.
This article discussed the various possible forces that can act on the waterfront-retaining wall during the earthquake and the available methodologies to compute them. The wave forces acting on the waterfront-retaining structures can be branched into non-breaking waves, breaking waves and broken waves. Hydrodynamic pressure due to seismic shaking plays a vital role in the stability and must be considered from both seaward and landward sides if the backfill is permeable. Various guidelines available for the design of waterfront-retaining wall and their limitations are discussed. The recent modified pseudo-dynamic method overcomes limitations of the pseudo-static method and considers the effect of time, amplification and damping properties in the analysis. Consideration of excess pore pressure variation with time in the analysis is challenging and needs further research.
Investigation of Rainfall-Induced Landslides at the Hillslopes of Guwahati Region, Assam
Sarma C.P., Dey A., Krishna A.M.
Landslides constitute a major hydrogeological hazard component of the natural disasters that affect most of the hilly regions around the globe. The impact of rainwater infiltration in causing landslides is widely recognized. A landslide study has a two-way approach; local scale (slope stability analysis) and regional scale (landslide susceptibility and hazard assessment). For any of the above-mentioned approach, the determination of infiltration capacity, hydraulic conductivity and characterization of the soil strength behaviour under different wetting and seepage conditions are the first and foremost steps. Hillslopes mostly consist of residual soils in unsaturated condition, thus rendering the conventional soil mechanics approach to be inadequate for the assessment of the stability of such slopes. To assess the potential susceptibility to rainfall-induced landslide, an effective modelling of the changes in water content and matric suction in response to rainfall infiltration is essential. Local scale approach gives a framework to address the slope stability and the effect of the various parameters in detailed manner. To address the uncertainty issues, probabilistic methods are developed. Models based on infinite slope stability model coupled with a hydrological model, within a grid-based GIS framework, is developed to evaluate the stability condition of a region. The simulation results of such models can be used to generate landslide susceptibility and hazards map of a particular region.
The 2017 July Northern Kyushu Torrential Rainfall Disaster—Geotechnical and Geological Perspectives
Hazarika H., Yamamoto S., Ishizawa T., Danjo T., Kochi Y., Fujishiro T., Okamoto K., Matsumoto D., Ishibashi S.
In July 2017, localized and torrential rainfall caused many landslides, debris flows, and flooding of rivers resulting in devastating damage to several areas of the Fukuoka and Oita prefectures of Kyushu, Japan. The authors conducted an extensive investigation of the damage covering several cities, towns, and villages of the Fukuoka and Oita Prefectures. The areas suffered from the disaster have many complicated geologies and geomorphologies, which exacerbated the damage. In this research, the authors focused on the landslides and debris flows that occurred in the Otoishi River basin. The characteristics of slope failures are analyzed, and the failures are classified focusing on the geological features. Finally, the slope failure mechanism is discussed.
Evaluation of the Risk Distribution of the Debris Flow Occurred Using Numerical Simulation Subjected to Rockfall
Isobe Y., Inagaki H., Ohno H.
The Hiroshima torrential rain and sediment disaster that occurred from 19 to 20 August 2014, brought a huge disaster to the private house on the alluvial cone. It was conducted a debris flow disaster focusing on this alluvial cone. In this survey, it was found that in the hornfels distribution area, there are many stones and gravels and the matrix content is small, so the alluvial cone becomes steep and the debris flow does not reach relatively far. In other words, from the viewpoint of disaster prevention and disaster prevention, it is important to think about land use while keeping in mind that the slope of the alluvial cone in the range where the debris flow in the upper part of the alluvial azimuth falls directly differs from geology. Although prediction analysis has been tried from such a disaster case, it has not yet been reflected in the design. It is desirable to predict highly accurate predictive analysis, but first of all, it was calculated by a simple calculation method as much as possible.
Instability of Composite Breakwater Subjected to Earthquake and Tsunami and Its Countermeasures
Chaudhary B., Hazarika H., Murakami A., Fujisawa K.
Many breakwaters collapsed during the past earthquakes and subsequent tsunamis mainly due to their foundation failures. However, their failure mechanism has not been well understood. To the end, physical model tests were conducted to understand exact failure mechanism of breakwater subjected to an earthquake and subsequent tsunami. Furthermore, countermeasures are developed for breakwater foundation which can make the breakwater resilient against earthquake and tsunami-induced damage. Gabion and steel sheet piles were used as reinforcing elements for the foundation. Effectiveness of the developed reinforcing model were judge by performing shaking table tests and tsunami overflow tests.
Integrating Rainfall Load into Remedial Design of Slopes Affected by Landslides
Sivakumar Babu G.L., Ering P.
Early warning systems mitigate landslide risk by providing sufficient lead time to implement actions in order to protect persons or property. However, landslide risk cannot be mitigated effectively by early warning system alone because in the majority of cases it is not possible to transfer settlements and infrastructures within the given lead time. Therefore, slope remediation measures are suggested for sites with landslide activity. For slopes prone to rainfall-induced landsliding, it is important to correct the existing slope with respect to rainfall load. However, rainfall loads are not integrated into the design process of remedial measures and the destabilising effect of rainfall is not quantified. This study provides a procedural method for integrating rainfall load into the design of slope remedial measures. The method combines rainfall–landslide relation model with remedial slope design.
Extended Application of Cement-Based Grouting to Gravel/Boulder Ground Improvement
Ishii H.
The off-the Pacific Coast Earthquake Japan in 2011 resulted in serious damage on various structures and highlighted some new geotechnical engineering issues. This notified us that new ground improvement techniques are still required that can be applied under special execution condition to achieve retrofits ground improvement. As one of these techniques, this paper deals with a new cement-based grouting which is applied to gravel/boulder ground improvement. We first review conventional cement grouting, and introduce the new technique, then two experimental studies are shown. From these, the detail of the grouting practice is confirmed, and adaptability of the grouting is discussed based on the gravel/boulder size and plasticity of grouting material.
Spatial Distribution of Strength—Comparison Between Indian and Japanese Embankments
Nishimura S., Imaide K., Ueta T., Hayashi T., Inoue K., Shibata T., Chaudhary B.
The spatial distribution of N value inside the earth-fill dams and river dikes are identified by the sounding tests, and compared between in Japan and in India. In this research, the Swedish Weight Sounding (SWS) and the dynamic cone penetration (DCP) tests are employed as the test methods, and the spatial correlation structure of the ground can be identified with very short interval tests. Consequently, high resolution of the spatial distribution of N value could be visualized based on the survey results. Simultaneously, the difference between Japanese and Indian embankments of the river dikes and earth-fill dams has been clarified.
Elastic Modulus Estimation Using a Scaled State Parameter in the Extended Kalman Filter
Koch M.C., Murakami A., Fujisawa K.
The Elastic Modulus of soil is an important property both from a strength and settlement perspective. Back analysis using observation data in an EKF could prove troublesome considering the large difference in magnitude of the covariances of the observation noise and the state vector noise. A simple scaled formulation is developed wherein the Kalman Filtering is done with respect to a new scaled state parameter. The domain is subdivided into blocks and only a simple two-block case is considered. The Elastic Modulus is considered constant inside a block. The EKF using the scaled state parameter is successful in estimating the state of only one of the blocks.
