Grouted jetted precast reinforced concrete piling technology for no dredge seawall and land reclamation in Hong Kong

Conference Theme: Reclamation: Challenges and beyondSeawall and reclaiming land in Hong Kong have to be robust, cost-effective and environmentalfriendly. To achieve this goal, this paper introduces an innovative technology of originality for design and construction of continuous and impermeable seawall and land reclamation environmental-friendly and cost-effectively. It is called the grouted jetted precast reinforced concrete piling (GJPRCP) technology. It is briefly introduced at first. Applications are given for illustration afterward. The idea of GJPRCP based no dredge seawall and reclamation is presented and discussed with illustration of conceptual design and construction steps. It can form continuous and impermeable and robust reinforced concrete structural seawall. The seawall can be used as a continuous impermeable cofferdam and a diaphragm during the construction stage. Brief examination and discussion of both the practice of conventional dredge seawall and reclamation and the adoption of no dredge seawall and reclamation in Hong Kong can show that because of their high structural rigidity, the GJPRCP based no dredge seawall and reclamation can be acceptable, feasible and applicable in Hong Kong.published_or_final_versio

Gas inclusions and their expansion power as foundation of rock “locked in” stress hypothesis

About 35 years ago, Professor TAN Tjong-Kie proposed the hypothesis of rock “locked in” stresses and considered the “locked in” stresses were the failure cause of rock engineering projects. In recent years, Professor WANG Sijing and Professor QIAN Qihu have made some qualitative discussions on the hypothesis. However, this hypothesis has received very little attention and quantitative investigation. In this paper, the author puts forward and attempts to show that the tiny gas (or liquid) inclusions in contact rocks are a specific, concrete and measurable inclusion type of variable and considerable “locked in” stresses and kinetic energy. The pressure and volumetric expansion energy of a gas inclusion are a type of “locked in” (or sealed) stresses and internal deformation energy of actual existence and active power. The author gives the governing equations to calculate the pressure and volumetric expansion energy of gas inclusions, which is shown with calculation examples. The pressure of the gas inclusions is equivalent to the average value of the in-situ stresses in deep rocks. The gas inclusions, sealed in micro-defects or voids of deep rocks, are the common tensile or expanding volumetric force sources for the occurrences of many failures in the surrounding rocks of excavated or engineered caverns or tunnels in deep rock ground. Because of differences in the physical and mechanical properties of the surrounding rocks, the compressed and dense gas inclusions can cause the following three results and/or phenomena. They are (a) stable walls, (b) brittle fractures and (c) large deformation of the surrounding rocks. Hard and brittle intact rocks can have brittle fractures in the forms of rock burst, mine earthquake, rock split, and zonal disintegration. Soft and ductile intact rocks can have the deformation failure in the forms large deformation, creep and pressure bump accordingly. In addition, the gas inclusions with high pressure can be the source of abnormally high in-situ stresses in some special deep rock grounds

On cause hypotheses of earthquakes with external tectonic plate and/or internal dense gas loadings

This paper examines and compares the two loading systems and their associated energy and basic stress fields in elastic crustal rock mass for the cause of tectonic earthquakes. The first loading system is an external loading system and associated with the conventional earthquake cause hypothesis of active fault elastic rebounding. The second is a combined loading system where the first external loading system is added with a dense gas loading in the interior of deep crustal rock faults/defects. It is associated with the methane gas hypothesis for the cause of tectonic earthquakes. Five elastic stresses in rock solids with some idealized faults and caverns are presented to illustrate the similarities and differences of the stress fields and the possible rupture failure modes in association of the two loading systems. The theoretical results can show that any changes in the local stress concentrations due the external loading alone can be reflected and noticed in the corresponding stresses at the far field. On the other hand, any changes in the local stress concentrations due to the internal gas loading cannot be observed and distinguished in the tectonic stress field at the far distance. These theoretical results can be used to well explain the consensus of earthquake unpredictability with present technology. The theoretical results can further show that the external tectonic loading alone can only cause shear ruptures in crustal fault rocks with high compressive stresses, and such shear rupture or frictional failure is also difficult to occur because its shear plane has extremely high compressive normal stress. The combined loading can cause not only shear ruptures, but also tensile ruptures in crustal fault rocks, and such shear and tensile ruptures occur much easier since the rupture plane can have very low compressive or even high-tensile normal stress. It is argued that the earthquake energy is the volumetric expansion energy of dense gas mass escaped from the deep traps along crustal rock faults. The migration and expansion of the escaped dense gas mass in the crustal rock faults and defects cause the seismic body waves, the ground sounding, the seismic surface waves, the ground co-seismic ruptures and damages. Its rapid migration and expansion in thick water cause tsunamis in lakes and oceans. Its rapid migration and expansion in the atmosphere cause the sky to become cloudy. The dense methane gas is produced every day in the mantle and core of the Earth, migrates outward and accumulates and stores beneath the lower crustal rock in high compression. It forms a thin spherical layer of dense methane gas separating the cold crustal rocks and the hot mantle materials. Its leaking along deep faults or plate boundaries causes earthquakes and supplies to shallow gas and oil reservoirs beneath secondary traps in adjacent basins of the upper crustal rock mass.postprin

地下工程事故紧急搜救的快速气冲钻孔和实时监测

如何以最快的速度搜救地下工程事故中的被困人員,是完成救援任務的關鍵,筆者提出了自動監測鉆孔過程的DPM方法。該方法在以高壓空氣作為動力的潛孔錘旋轉沖擊鉆孔中,能夠自動、連續地對鉆孔過程實時數字監測和記錄。這種智能型監測鉆孔可以實時建立沿鉆孔深度各點的巖土體力學強度與空間分布,從而準確地測定地下洞室或巷道的位置及范圍。該技術起到快速搜索以及輸送新鮮空氣的作用,鉆成的孔洞可以將食物和水傳遞給被困人員。十多年來,實際數字鉆孔監測結果表明,這項研究的確可以精確測定和給出地下巖土體的力學強度。該方法可以有效地、具體地應用到地下工程事故緊急搜救工作中。 This paper presents a brief idea for an effective searching and rescuing people trapped in sealed underground spaces such as caverns and tunnels due to collapse of surrounding rock and soil masses.The idea is based on the fast construction hole drilling and its automatic digital monitoring.The drilling device is the compressed air-flow driven percussive-rotary drilling associated with a down-the-hole hammer.The drilling process monitoring allows an accurate and effective delinearing of the soil and rock strength and quality along the drill hole in real time,thus making it possible to quickly determine the location of the buried underground space and reach the people in the underground space,with the result that the compressed air-flow can flow into the buried underground space through the holes in the bit of the hammer.It follows that the method can come into effective and practical use for emergent searching and rescuing people trapped in buried underground space

On incorrectness in elastic rebound theory for cause of earthquakes

The elastic rebound theory was developed 100 years ago from the observations of co-seismic surface ruptures induced by the 1906 California Earthquake. It is only partially correct because it associates earthquakes with geological faults. However, it is inconsistent and even violates many other phenomena that were present before, during and after earthquakes. Numerous failures have been encountered and experienced in the tremendous efforts using the elastic rebound theory in the prediction of earthquakes over the past 100 years. Many current seismo-geologist and seismologists have lost their original goals to predict earthquakes and turned to believe that earthquakes are unpredictable with present techniques. All these problems are due to the fact that the incorrect elastic rebound theory for cause of earthquakes was used in the investigation and prediction of earthquakes. The paper also shows that the energy released during earthquake is not the elastic stress and strain energy accumulated in brittle crustal rock solids during relative movements of tectonic plates. The released energy is the volumetric expansion energy of highly compressed and dense natural gas rapidly escaped from its deep crustal traps via fault channels. This gas hypothesis for the cause of earthquakes would make earthquake predicable in the near future.postprin

Yue’s solution of classical elasticity in n-layered solids: Part 1, mathematical formulation

This paper presents the exact and complete fundamental singular solutions for the boundary value problem of a n-layered elastic solid of either transverse isotropy or isotropy subject to body force vector at the interior of the solid. The layer number n is an arbitrary nonnegative integer. The mathematical theory of linear elasticity is one of the most classical field theories in mechanics and physics. It was developed and established by many well-known scientists and mathematicians over 200 years from 1638 to 1838. For more than 150 years from 1838 to present, one of the remaining key tasks in classical elasticity has been the mathematical derivation and formulation of exact solutions for various boundary value problems of interesting in science and engineering. However, exact solutions and/or fundamental singular solutions in closed form are still very limited in literature. The boundary-value problems of classical elasticity in n-layered and graded solids are also one of the classical problems challenging many researchers. Since 1984, the author has analytically and rigorously examined the solutions of such classical problems using the classical mathematical tools such as Fourier integral transforms. In particular, he has derived the exact and complete fundamental singular solutions for elasticity of either isotropic or transversely isotropic layered solids subject to concentrated loadings. The solutions in nlayered or graded solids can be calculated with any controlled accuracy in association with classical numerical integration techniques. Findings of this solution formulation are further used in the companion paper for mathematical verification of the solutions and further applications for exact and complete solutions of other problems in elasticity, elastodynamics, poroelasticty and thermoelasticity. The mathematical formulations and solutions have been named by other researchers as Yue’s approach, Yue’s treatment, Yue’s method and Yue’s solution.postprin

Cause and mechanism of great earthquakes due to highly compressed methane gas mass trapped in subduction faults

This paper uses the highly compressed methane gas mass model to interpret and explain the occurrence of great earthquakes at subduction fault with long recurrence intervals[1]. The gas model can be described as follows with the reference to Figure below. The subduction faults are weak zones and can become gas reservoirs generated in deeper rocks. With time t, the mass M(t), volume V(t), pressure P(t) and temperature T(t) of the reservoir gas can change and increase. At the fault rupturing of great earthquakes (t = 0), a huge amount of highly compressed gas mass ...postprin

Development of classical boundary element analysis of fracture mechanics in gradient materials

Over the last decade, the authors have extended the classical boundary element methods (BEM) for analysis of the fracture mechanics in functionally gradient materials. This paper introduces the dual boundary element method associated with the generalized Kelvin fundamental solutions of multilayered elastic solids (or Yue’s solution). This dual BEM uses a pair of the displacement and traction boundary integral equations. The former is collocated exclusively on the uncracked boundary, and the latter is collocated only on one side of the crack surface. All the singular integrals in dual boundary integral equations have been solved by numerical and rigid-body motion methods. This paper then introduces two applications of the dual BEM to fracture mechanics. These research results include the stress intensity factor values of different cracks in the materials, some fracture mechanics properties of layered rocks in rock engineering.postprin

Stresses and displacements in functionally graded materials of semi-infinite extent induced by rectangular loadings

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