Determination of the maximum traction force of the screw working body when piercing the soil

Laying of gas distribution pipelines, water mains, sewerage systems, power cables and communication cables is performed both by laying it in an open trench and by trenchless methods.

Study on the vibration isolation performance of an open trench–wave impedance block barrier using perfectly matched layer boundaries

One of the problems associated with vibration pollution is ground vibration. In view of the isolation of objects protected from ground-transmitted vibrations, a novel type of vibration isolation barrier, an open trench–wave impedance block, is proposed. Based on the perfectly matched layer absorbing boundary, the two-dimensional finite element method in the frequency domain is used to investigate the vibration isolation performance of the open trench–wave impedance block barrier system for reducing the vibration generated by a vibration source. Firstly, the governing equation of the perfectly matched layer absorbing boundary is established in the frequency domain by using complex coordinate stretching. Secondly, using Galerkin approximation technology, the calculation formula of the second-order non-splitting perfectly matched layer with the displacement as the basic unknown quantity is given for the finite element method in the frequency domain. Finally, the influence of the physical parameters (modulus ratio between ground and wave impedance block), geometric parameters (dimension and layout of an open trench–wave impedance block barrier, including embedded length and width) and the load parameters (exciting frequency of the vibration source) on its vibration isolation performance is researched. The results show that the open trench–wave impedance block barrier system can provide a more flexible and efficient isolation barrier for ground vibration control.

FUNGSI MANGROVE SEBAGAI BIOFILTER LIMBAH BUDIDAYA UDANG VANAME PADA TAMBAK INTENSIF SUPM NEGERI BONE

This research was conducted in Juli-September 2019 in the Intensive Bone Pond SUPM Negeri Bone, Bone Regency. This study aims to: (1) Describe the condition of the study site for pond intercropping patterns; (2) Knowing the type and density of mangroves at the study site; (3) Assessing the role of mangroves as biofilter for the pollution of vaname shrimp pond cultivation. The method used in data collection is done by direct measurement to the field for water quality at the location of the pond, the type and density of mangroves determined by using transects. The results showed that the pond intercropping pattern used in the Bone State SUPM Pond was a model of an open trench pond. The type of mangrove that dominates the research location is Rhizopora mucronata and for vegetation density each station was different where in the tree category station 1 had a vegetation density of 0.48 ind / m², station II was 0.87 ind / m², station III was 1.06 ind / m². For the stake category 1 station has a vegetation density of 0.24 ind / m², station II is 0.08 ind / m², station III is 0.68 ind / m². For the seedling category station 1 has a vegetation density of 77 ind / m², station II is 32 ind / m², station III is 15 ind / m². Mangroves in the vicinity of SUPM Bone Bone can play a role as biofilter for the pollution of vaname shrimp aquaculture results with measurements of water quality before and after passing through mangroves decreased

Cultural Resources Survey of Antiquities Permit Portions of the Orion Refurbishment Project in Midland and Mitchell Counties, Texas

Gray and Pape, Inc., performed an intensive pedestrian cultural resources survey of the Area of Potential Effects of permitted segments of proposed pipeline refurbishment located in Midland and Mitchell Counties, Texas. To date, no federal permitting has been identified for the project. However, approximately 3.2 kilometers (2 miles) of the project area are located on lands owned by the City of Midland and the City of Colorado City, and will be reviewed under the Texas Antiquities Code (Texas Natural Resource Code, Title 9, Chapter 191), Permit number 8677. The area surveyed amounts to approximately 20 hectares (50 acres) of survey corridor, which is considered the Area of Potential Effects. A records and literature review of the project location prior to survey identified two previously recorded archaeological sites and two previously conducted surveys within a 1.6-kilometer (1-mile) radius of the project. Fieldwork was conducted in January and March of 2019. The project required 156-person hours to complete and involved archaeological reconnaissance and shovel testing throughout the entire Area of Potential Effects. A total of 116 shovel tests were excavated along current and previously planned routes, of which 10 were positive for cultural materials. One new previously unrecorded site was identified as a result of survey. Site 41MD58 consists of a low-density surface and buried lithic scatter of a limited number of artifacts and artifact types. The surface of the resource area showed clear disturbance from the adjacent pipeline right-of-way and agricultural activities. A portion of the site was in the process of being disturbed at the time of site delineation by pipeline activities unrelated to the current project consisting of an open trench and associated spoil. Shovel tests within the site showed a lack of integrity primarily as a result of natural and artificial processes resulting in the dispersion of artifacts. The site did not contain temporally or culturally diagnostic artifacts and no artifacts were collected. Nor were any cultural features or historic-age standing resources encountered in the field. Based on the paucity of artifacts, lack of diagnostic materials, and lack of integrity, the site portion located within the Area of Potential Effects is recommended not eligible for State Antiquities Landmark or National Register status. Gray & Pape, Inc. recommends no additional archaeological work for the site or surveyed portions of the project detailed in this report. However, Gray & Pape, Inc. recommends that an unanticipated discoveries plan be put into place in the event that discoveries take place during construction. Gray & Pape, Inc. submitted project records to the Center of Archaeological Studies at Texas State University.

FINITE ELEMENT ANALYSIS OF OPEN TRENCH SEISMIC VIBRATIONS BARRIERS

Rectangular open or filled trenches (wave barriers) are often used in engineering practice to reduce ground vibrations caused by surface sources. Modeling of such barriers by the finite element method in order to assess their effectiveness is presented in this paper.

Vibration Induced by Subway Trains: Open-Trench Mitigation Analysis in the Time and Frequency Domains

In this paper, we analyse the mitigation effects of open trenches on the vibrations induced by subway trains. The study is performed by using both physical model tests and numerical simulations. The effectiveness is evaluated by calculating the frequency response function (FRF) and the vibration acceleration peak (VAP) in both time and frequency domains. The experimental and numerical results demonstrate that the open trench has clear effects on the dynamic soil response. Both time and frequency domain results suggest that the dynamic response of the soils beyond the open trenches could be significantly affected, due to the existence of the open trench. According to the frequency domain analysis, the inclusion of open trenches could effectively reduce the soil response in a higher frequency range. Due to reflection effects at the boundaries of the trench, an amplification of the soil response in front of the open trench is observed. Parametric study by means of numerical simulations is also performed. The width of the open trench demonstrates negligible effects on the dynamic soil response, whilst the trench depth exhibits a large influence on the trench isolation performance. With an increase in the trench depth, the isolation performance is significantly improved. It is concluded that the open trenches perform well as an isolation barrier, in mitigating the vibration induced by subway trains.