Adjacent Constructions Research Articles

Numerical investigation on impact of excavations in influence zone of existing MRT tunnels

ABSTRACT Due to a high demand of space utilisation in metropolitan area, the existing tunnels, which are normally used for underground transportation and service utilities, can be suffered from the impacts caused by the adjacent constructions. In general, the protection zone of a tunnel is developed based on the assumption of shear plane of soil, rather than the soil–structure interaction. The assessment of the impacts of new construction nearby the existing tunnel is thus essential for improving the protection zone. 3D finite-element analyses are conducted for the case of the mass rapid transit (MRT) tunnels in soft ground. The impacts on the MRT tunnels from two possible underground construction cases (i.e. open cut and pipe jacking) are investigated in terms of tunnel deformations and changes in tunnel lining moment. The advantages of using 3D analysis are to model the realistic soil–structure interactions and to observe the multidirectional impacts on MRT tunnels. The results show that the bending moments increased by both open cut and pipe jacking construction activities are relatively small. For the tunnel deformations, most cases are sufficiently secure, but only in some cases, the deformations of tunnel lining almost reach the limit of 6 mm. However, it is highly recommended that they are still required to numerically examine in case by case

Weakening behavior of waterproof performance in joints of shield tunnels under adjacent constructions

Weakening behavior of waterproof performance in joints of shield tunnels under adjacent constructions

The Mechanical Waves Effects Induced by the Underground Rock Blasting Technology on Adjacent Constructions

The Mechanical Waves Effects Induced by the Underground Rock Blasting Technology on Adjacent Constructions

Evaluation of tensile properties of early-age concrete-block masonry assemblages

Masonry is one of the most traditional and economical modes of construction worldwide. Although many codes and standards are available to evaluate fully-cured masonry assembly properties for the design of masonry structures, there is a gap in understanding the properties of freshly laid masonry and the design of newly constructed unsupported masonry walls. Early-age (within the first seven days) masonry at the construction site possesses reasonably high compressive strength but considerably low flexural tensile strength, making it vulnerable to lateral loads due to wind, earthquake, and adjacent constructions. This has resulted in numerous incidents of structural damage and injury to workers leading to more stringent and conservative construction bracing techniques. In this paper, the tensile properties of early-age concrete block masonry have been assessed by conducting comprehensive numerical and experimental studies on mortar and masonry assemblage. Outlier analysis has been applied to the experimental data to minimize uncertainties and biases. The modulus of elasticity and tensile strength of the masonry assemblages against the curing time has been obtained using a statistical analysis conducted over a large sample size. The results show that the tensile strength of masonry remains nearly insignificant until 3–7 h, then increases logarithmically. It is also observed that the bond between the mortar and blocks is the weakest part of the masonry assemblages, and the failure happens in the unit-mortar interface bond rather than in the fresh mortar. The modulus of elasticity and tensile strength of early-age masonry assemblages are 38% and 18% of the corresponding properties of early-age mortar material alone, respectively. Therefore, the quantification of assembly properties cannot be ascertained from material testing alone within seven days of construction. It is anticipated that the proposed research will provide valuable design properties leading to improved guidelines needed to design control devices (e.g., temporary bracing) for concrete-block masonry construction.

Displacement measurement of large structures using nonoverlapping field of view multi‐camera systems under six degrees of freedom ego‐motion

AbstractIn this work, a non‐overlapping field of view (FOV) multi‐camera system (MCS) has been proposed to realize the motion self‐compensation, which can be flexibly arranged according to the field situation. The challenges of ensuring a complete fixed measurement platform owing to the self‐weight, unexpected collisions, and adjacent engineering constructions have been addressed in this study. MCS can be fixed on an unstable platform and employ two or more correcting cameras, without an overlapping FOV, to measure and compensate the six degrees of freedom (6‐DOF) ego‐motion of the platform, with high accuracy. The numerical simulation results show that, under the same configuration conditions, the 6‐DOF motion estimation accuracy of the proposed method is better than that of the Perspective‐n‐Points methods, especially for the estimation accuracy of the out‐of‐plane motion and the roll motion of the camera. The field demonstration has been performed on a suspension bridge, and the results demonstrate that the deflection measurements provided by the proposed MCS are consistent with those provided by the Robotic Total Station. The proposed MCS, which is not restrained by a strictly stable platform, proves to be an effective method to compensate for the errors induced by the platform ego‐motion, and it can meet the requirements of the displacement measurement of large structures needing high precision.

Prediction of ground surface settlement induced by twin tunnelling in urban areas

Tunnelling in urban areas is growing in response to efficient transportation, many urban tunnels are constructed in soft ground at shallow depths. Urban tunnels are usually constructed as twin-parallel tunnels and their adjacent constructions may cause ground settlements that distort and damage the existing structures and utilities above the tunnel. In the past few decades, tunnel boring machines have been used to drill in increasingly difficult geotechnical conditions such as soft ground like soft clay. Metro Line 3 of the Hanoi metro system is designed of twin tunnels horizontally aligned in soft ground. The prediction of ground movements is an important part of the planning stage of any urban tunnelling project. This paper presents the results of numerical simulation by using ABAQUS finite element software to predict the vertical displacement at the surface caused by twin tunnelling of Hanoi pilot light metro line 03. According to numerical simulation results, the maximum vertical displacement at the surface caused by the left line tunnel and twin tunnels bore excavations is values of 12.8 and 21.3 mm, respectively. The maximum vertical displacement can be reached after the shield passes by a distance ranging from 30÷40 m. Twin tunnelling only affects the maximum vertical displacement at approximately 20÷30 m before excavation face tunnel. After the left line tunnel bore excavations, the magnitudes of the vertical displacement directly above the face tunnel (x = 0 m) is 7.9 mm coinciding with 61.7% of the maximum vertical displacement. After the twin tunnels bore excavations, The maximum vertical displacement directly above the face tunnel (x = 0 m) is 13.1 mm coinciding with 61.5% of the maximum vertical displacement.

Micro-deformation monitoring technology and optimization method for the rail surface of high-speed railway operation lines with adjacent constructions

Micro-deformation monitoring technology and optimization method for the rail surface of high-speed railway operation lines with adjacent constructions

The influence of the water flow on the stability of the coastal slope and adjacent transport constructions

The mechanical behavior of the frozen soil is dynamic and complex. When formulating the strength-to-deformability ratio, it is important to understand the characteristics of the soil, which is being estimated. At the same time different soil samples that have analogical physical characteristics in the unfrozen state may behave differently after freezing and during thawing, as frozen relict and seasonally thawed soils behave differently. All this requires a number of laboratory researches, which will then allow to determine the soil parameters for a specific project. In the hydraulic laboratory, experiments were conducted to study the strength of the different samples of frozen soil under the influence of the water flow and the same load.

Prediction of ground surface settlement induced by twin shield tunnellings in urban conditions

Tunneling in urban areas is growing in response to the increased needs for efficient transportation. Many urban tunnels are constructed in soft ground at shallow depths. Metro tunnels are usually constructed as twin-parallel tunnels and their adjacent constructions may lead to surface deformation, affecting the surface environment and the safety of the tunnels. Shield tunnelling is a commonly used as construction technique because it is very effective in reducing ground deformations and thus damage to urban infrastructure. The paper presents a 3D simulation of shield tunneling machines via the finite element code Abaqus and analysis model of ground surface settlements induced by a construction of twin-parallel tunnels. The results show that ground surface settlements induced by a construction of the left tunnel causes surface settlements of about 22÷24 mm and after the construction of both tunnels, it will cause ground subsidence has the greatest value of 33÷35 mm.

СТИЛІСТИЧНА СИМЕТРІЯ В МЕФОДІЇВСЬКОМУ ПЕРЕКЛАДІ ПІСНІ НАД ПІСНЯМИ

The article is devoted to the analysis of stylistic symmetry in Methodius' translation of the Song of Songs. The study was conducted from a rather unexpected position, namely – using the linguo-folkloristic approach. The rationale for this approach is that it's subject is a folklore text, a collection of wedding songs, which later underwent exquisite literary and book processing. It is concluded that the realizations of the poetic technique of stylistic symmetry found here are based on the same syntactic construction of the members that make it up. Parts of this construction are presented as semantic additions to each other. Adjacent constructions similar in syntactic structure were found with sublime depictions and chants of brides, their beauty and perfection, love. Based on the studied material, it was found that, although in all found examples the components of stylistic symmetry are not identical as required by the logic of reception, but in some of them at least a third of the verbal material of the first. Naturally, in such a poetic text as the Song of Songs, one could expect to come across a significant number of tropes and as part of the verbal embodiment of a stylistic device based on semantic parallelism. In fact, in the vast majority of examples they were recorded in both parts of stylistic symmetry. These are comparisons, metaphors, epithets, allegories, hyperboles, highly artistic paraphrases, etc. Twice stylistic symmetry was built on the antithesis, in particular it was found in the praise of the bride. It has been found that the stylistic symmetry in the Song of Songs is productively explored in terms of ways to express the expressiveness of syntax: how, by what means similar or identical human emotions are reflected in related syntactic constructions. As for the reproduction of this Middle Eastern stylistic device in the Methodist translation of the Song of Songs, it demonstrates unsurpassed harmonious examples of expressive expressiveness and original variation of thought.

Deformation Characterisation and Distress Diagnosis of a Metro Shield Tunnel by Adjacent Constructions

This paper presents a case history of the developmental effect of a large‐area excavation, 8 high‐rise main buildings, a series of annex constructions, and ground overloaded building demolition on the deformation characteristics of an existing shield tunnel within Guangzhou Metro Line No. 1 in close proximity to the development. The shield tunnel lies in a sandy layer of the typical upper‐soft and lower‐hard strata in Guangzhou district, and the deformation of the tunnel has been monitored since the tunnel was put into operation. The monitoring results reveal that the adjacent construction induces an excessive tunnel settlement with a maximum of 14.4 mm and an excess tunnel displacement with a maximum of 5.2 mm, which are within the corresponding limitations of the codes for the safe operation of urban rail transit tunnels. While the station expansion project is being conducted beside the tunnels, a series of tunnel distresses, including large‐area water seepage, spalling concrete blocks, and segmental cracks, are recorded. Our field monitoring data indicate that the tunnel is subjected to further vertical contraction and horizontal expansion due to the station expansion project, and a maximum tunnel flattening rate of 36.78% is detected. Furthermore, the tunnel linings are studied numerically and theoretically to obtain the limitations of tunnel deformation and discuss why tunnel distresses of water seepage, concrete spalling, and segmental cracking occur. Finally, on the basis of the analyses and discussions above, counteracting corrective measures, including compensation grouting soil strengthening and bonded steel plates, are adopted as exterior and interior strengthening methods, respectively, to eliminate further tunnel distresses and ensure safe operation. The lessons learned and summarized in this study may help prevent similar tunnel distresses from reoccurring in the future.

A Study on the Review of Repair Methods and Repair Materials for the Prevention of Fire spread of Building Exterior Materials

국내의 경우 2018년도에 시행한 가연성 외장재 설치 건축물 현황조사결과 147,559동의 건축물이 이에 해당되는 것으로 조사되었으며, 상층부 및 인접건축물로의 화재확대사례는 연간 약 3,500건, 외장재에서 시작한 화재건수는 연간 약 1,500건 이상 발생하는 등 의정부 화재, 제천스포츠센터 화재와 같은 유사한 화재발생의 위험성이 내포되어 있다. 본 연구에서는 유사한 화재 재발방지를 위해 가연성 외장재가 시공된 건축물의 보수공법에 대해 조사하고 각 각의 보수재료 성능검증을 실시하였다. 보수방법의 경우 기존의 건축물 마감재를 제거한 뒤 보수재료로 보강하는 방법과 기존 마감재를 제거하지 않고 면고르기를 실시한 뒤 보수재료를 부착하는 방법을 제안했다. 또한 드라이비트 및 보수재료로서 방화석고보드, 미네랄 울, 경질우레탄 폼, 세라믹보드, ALC 패널 등 6가지 재료를 대상으로 콘 칼로리미터 시험을 실시하고 해당 재료들에 대한 기초 연소 성능을 조사하였다.In Korea, the results of a field survey on the construction of flammable exterior materials implemented in 2018 revealed that 14 7,559 buildings belong to this category. It was found that the fire spreading cases in upper and adjacent constructions are about 3,500 per year, the fires of starting in flammable exterior material are about 1,500 per year. In this study, we investigated the repair method of buildings constructed by flammable exterior material and conducted performance verification of each repair materials for prevention of similar fire. In the case of the repair method, a method of reinforcing with a repair material after removing the existing building finishing material and a method of attaching the repair material after performing the face finishing are proposed. In addition, we conducted cone calorimeter tests of 6 materials such as fireproof gypsum board, mineral wool, hard urethane foam, cera mic board and ALC panel as dryvit and repairing materials, and investigated basic combustion performance of that materials.

Influence Zone Division and Risk Assessment of Underwater Tunnel Adjacent Constructions

Compared with ordinary tunnels, the influence analysis of underwater tunnel adjacent constructions is more complicated. At present, the empirical method used to divide the influence zone of the tunnel adjacent constructions has great uncertainty. So it is of great significance for actual construction and design to determine the influence zone accurately according to theoretical calculations. In this paper, based on the Hoek–Brown nonlinear failure criterion of rock mass and taking seepage factor into account, the stress state of rock mass around the underwater tunnel adjacent constructions can be deduced by elastoplastic theory. Then combined with the concept of “loose zone-bearing zone”, the influence zone division method of underwater tunnel adjacent constructions is proposed, and it is applied to the analysis of engineering examples. Through the deduced theoretical formulas, the influence zone of underwater tunnel adjacent construction can be divided into extensively strong, strong, relatively strong, weak, and noninfluence zones. Corresponding the influence zones with the risk levels in the code, different control measures are adopted for different risk levels, which can provide certain guidance for the design and construction of tunnel in practical engineering.

The Acoustics ofContiones, or How Many Romans Could Have Heard Speakers

AbstractContiones– assemblies during which important Roman politicians discussed the laws proposed at the People’s Assemblies as well as candidates for the offices and presented their opinions to the Roman people – are considered by some scholars as one of the central institutions and rituals of the Roman Republic. Considering the rolecontionesplayed in the political life of the Roman Republic, we can ask how many Romans participated in them. In our paper we present results of acoustic analyses of two places at the Forum Romanum that we know were platforms for speakers atcontiones: theRostraand the podium of the Temple of Castores. The main goal of our study was to establish the maximum number of participants that could have heard speeches inteligibly. To do that we used a 3D model of Forum Romanum considering not only the geometry but also the acoustic parameters of materials used to construct therostraand adjacent constructions. Based on the sound power level of a speaker and possible noise sources, on which the recipients were exposed to, we established areas where speeches could have been heard and understood. This in turn allowed us to estimate the maximum number of recipients.

Analysis of Deep Foundation Pit Construction Monitoring in a Metro Station in Jinan City

In order to study the deformation law of adjacent building structures, surface settlement, displacement of supporting piles, axial force and variation of water level during different excavation stages of deep excavation construction, the deep foundation pit project in the M1 line of the Jinan Metro was used as the background, and the data from field measurement of excavation and support were analyzed. The results show that the horizontal displacement of the pile presented a pronounced “bow” shape with the excavation of the foundation pit. The maximum horizontal displacement of the pile appeared at one third of the top of the pile, with a maximum of 31.98 mm. The maximum value of monitored axial force was 3100 kN, which was much less than the control value of 6847 kN. The maximum axial force appeared on the second steel support. The axial force of the first reinforced concrete support rapidly increased with the time. It was considered that the initial bearing capacity of the concrete was low, so the axial force of the concrete support was smaller than the steel support. The strength and load-bearing capacity of concrete increased in the later period, which resulted in a rapid increase in axial force. At the same time, during the process of setting up or dismantling the support, the attention should be paid to the axial force change of the adjacent support to prevent the danger caused by the abrupt change of the axial force. The maximum settlement value of the building appeared at the two corners far from the foundation pit, with the value of 4.3 mm. When the constructions were 34 m away from the deep foundation pit, the impact of dewatering on the building was greater than that of the foundation pit excavation, and he effect of the dewatering on the variational soil texture in this area was different. The maximum angular variation of adjacent constructions was 1/16,050, which was less than the 1/5000 of the minimum angular variation. The foundation pit structure and building were in a safe state, and the layout of the supporting structure was reasonable.

Back analysis of an embedded retaining wall for a deep excavation in Bucharest

AbstractRetaining system design involves a careful analysis and knowledge of the geotechnical parameters, as well as the soil‐retaining structure interaction, which is usually accomplished using the finite element method (FEM). Finite element method allows the use of complex constitutive models for all materials, especially for soil behaviour. The aim of this paper is to present the back analysis in terms of calibration of the numerical model used for modelling the self‐supported embedded wall composed of tangent piles for an 8 m deep excavation in Bucharest. Soil parameters were calibrated based on the result obtained from monitoring measurements performed during the execution of the deep excavation through inclinometers installed in the embedded wall, extensometers and incline‐extensometer in the excavation and topographical measurements for both retaining wall and adjacent constructions.

Sparsity and Geometry Preserving Graph Embedding for Dimensionality Reduction

Graph embedding is a very useful dimensionality reduction technique in pattern recognition. In this paper, we develop a novel discriminative dimensionality reduction technique entitled sparsity and geometry preserving graph embedding (SGPGE). SGPGE can not only capture the sparse reconstructive relationships among training samples but also discover the intrinsic geometry and latent discrimination from high-dimensional data. In SGPGE, the novel ways of constructing global and local adjacent graphs are developed. The built graphs with discriminant and geometrical information are more informative in graph embedding. Integrating the sparse reconstruction with the designed local and global adjacent graph constructions, SGPGE newly characterizes with-class sparsity and geometry preserving scatter, between-class sparsity and geometry preserving scatter and local sparsity and geometry preserving scatter to formulate the objective function of dimensionality reduction, and learns the discriminative transformation matrix using maximum margin criterion. Moreover, we also propose three variants of SGPGE. Experimental results on six public face datasets have demonstrated that the proposed methods are effective dimensionality reduction techniques with very good performance for classification in the embedding subspace.

Approaches for the boundary envelope design of an enhanced façade test facility

The state of the art experiments to investigate the hygrothermal performance of the whole constructions are often defined for one-dimensional transport processes only and typically executed by using the guarded hot-box / cold-box setup. The guard function is supposed to minimize the influence of the energy fluxes through the adjacent constructions enveloping the air-conditioned sides. However, measuring and testing the tall or complex geometric thermal bridge constructions are rarely done and remain a challenge.Therefore an innovative climate chamber design will be established. It is designed to investigate the performance of multifunctional active façade systems, including the roof components and its constructive joints. One of the challenging tasks is the provision of the pre-defined stable boundary conditions. This is an immanent precondition for the calibration and validation of simulation models.Particular difficulties in this setup are the specimen dimensions of up to 4x7 meters and corner details of corresponding size. The specifics of the guard construction for the hot-box side, as well as details of equipment connections, joints and breakthroughs are illustrated and discussed. Approaches to prevent the unintended heat and moisture flows at the boundaries of the specimen are also debated.

Induced Settlement Reduction of Adjacent Masonry Building in Residential Constructions

Many buildings and heritages are yearly damaged due to new construction plans in vicinity of them. Current engineering practice in Iran lacks unfortunately regulations to enforce the designers of new buildings to re-evaluate the structural integrity of adjacent old buildings which are prone to unacceptable induced settlement and distortions. To damage assessment of old building, deflection ratio was used for unreinforced load-bearing wall (masonry) building. In this paper some practical methods like story limits for the new buildings according to the specification of old structure, improvement of shallow foundations and increasing the embedment depth of new foundations have been studied in order to decrease the settlement and undesirable effects of adjacent constructions. Parametric studies using numerical analysis, Flac3D, have paved the way how above mentioned methods can remedy the problem. So induced consolidation settlements due to new construction in adjacent building were studied. In conclusion, increase of admissible story of new building up to one floor by increase of embedment depth as much as one meter and three floors by using of mat foundation instead of single footing were highlighted these methods.

Water, centering, and the beginning of time at Middle Preclassic Nixtun-Ch'ich', Petén, Guatemala

What determines a site’s location? In the ceremonial core of the lowland Maya site of Nixtun-Ch'ich', Guatemala, a large depression lies east of an E-Group (quasi-solar-“observatory”) architectural complex. Excavations in this depression (Fosa Y) revealed a large, deep—and thus far bottomless—cavity in the limestone filled with water-deposited sediments containing Terminal Early and Middle Preclassic (∼1000–400BCE) pottery and other remains. The upper periphery of Fosa Y was lined with amphitheater-like stone terraces, which framed a rich late Middle Preclassic ritual midden. Interpretations of the role of Fosa Y and adjacent constructions relate to deep structures of Mesoamerican belief systems, from Olmec to Aztec, concerning water, mountains, solar stations, the Underworld, and Creation. Fosa Y was likely a natural sinkhole (cenote), rather than human-made, and thus a powerful and deeply symbolic feature of the terrain for the earliest settlers and a compelling setting for integrative community rituals. It centered the east-west axis of this unusual, gridded, early city and its sacred landscape.