Initial support distance of a non-circular tunnel based on convergence constraint method and integral failure criteria of rock

For deep tunnel projects,selecting an appropriate initial support distance is critical to improving the self-supporting capacity of surrounding rock.In this work,an intuitive method for determining the tunnel’s initial support distance was proposed.First,based on the convergence-confinement method,a three-dimensional analytical model was constructed by combining an analytical solution of a non-circular tunnel with the Tecplot software.Then,according to the integral failure criteria of rock,the failure tendency coefficients of hard surrounding rock were computed and the spatial distribution plots of that were constructed.On this basis,the tunnel’s key failure positions were identified,and the relationship between the failure tendency coefficient at key failure positions and their distances from the working face was established.Finally,the distance from the working face that corresponds to the critical failure tendency coefficient was taken as the optimal support distance.A practical project was used as an example,and a reasonable initial support distance was successfully determined by applying the developed method.Moreover,it is found that the stability of hard surrounding rock decreases rapidly within the range of 1.0D(D is the tunnel diameter)from the working face,and tends to be stable outside the range of 1.0D.

Stability Analysis of Large Section Rocky Tunnel Support Structure

In order to study the stress characteristics of the initial support and secondary lining of the large section tunnel and to solve the problem of secondary lining cracking during operation. Taking the large section tunnel in Zihong village, Qi County as the research object, a numerical simulation method was used to establish a finite element model of the large section tunnel. So as to simulate and analyze the stress characteristics of the support structure of this tunnel. Through the simulation of the initial support and second lining of this large section tunnel in terms of displacement, stress, plastic zone damage and anchor shaft force, the results show that as the excavation progresses, the stress and displacement on the surface of the newly excavated tunnel profile is faster, especially at the side walls and arch footings, the stress and displacement values are slightly larger than other characteristic points, but the final values are stable and converge, and are basically consistent with the field monitoring results, which indicates that this support system is basically in stable state. Therefore, during the tunnel excavation and support process, special attention should be paid to the stability of the sidewalls and footings, and the results of this study will be of great practical significance for tunnel construction and maintenance.

Abia State Telehealth Initiative: A Novel Ingenuity

In Nigeria, Universal health coverage has been sub-optimal due to limited access and inequality. This is worsened by poor health-seeking behavior due to out-of-pocket expenditure health system financing being practiced by a greater percentage of the population. However, leveraging on the increasing population of Nigerian’s using communication technologies provides a viable and robust platform for improving patient’s care. Consequently, tele-health initiative provides a complementary approach to improving access to quality health and universal health system coverage. Tele-health initiative is Abia state’s input in progressing the Universal Health Coverage mandate of the Federal Government of Nigeria, anchored on the e-Health policy of Nigeria, after its adoption at the 58th NCH in Sokoto in 2016, of which Abia became the pioneer state for the Project. Abia state’s telecommunication market caters to almost 3.5 million active subscribers, making it the single largest provider of services in the state. Objective: The project is designed to ascertain the impact of the tele-health initiative on healthcare service coverage in Abia State. Methodology: This is a descriptive study with the quantitative and qualitative arm. The study was conducted in all the seventeen local government areas in the State. Result: 29,488 incoming calls were related to general health inquiries about basic information, counseling, and support that improved callers’ knowledge and attitude towards their health, concerns, and symptoms. Also, 66.8% of all calls (19,382) were for routine health information, complaints on mild everyday symptoms, chronic disease management, and follow-up care. About 29.6% of total calls (8751) were made by persons seeking information on socially stigmatizing topics and conditions.

Why a mosquito leg possesses superior load-bearing capacity on water:Experimentals

Mosquitoes possess the striking ability to walk on water because each of their legs has a huge water supporting force（WSF） that is 23 times their body weight.Aiming at a full understanding of the origins of this extremely large force,in this study,we concentrate on two aspects of it：the intrinsic properties of the leg surface and the active control of the initial stepping angle of the whole leg.Using a measurement system that we developed ourselves,the WSFs for the original leg samples are compared with those whose surface wax and microstructures have been removed and with those of a different stiffness.The results show that leg f exibility plays a dominant role over surface wax and microstructures on the leg surface in creating the supporting force.Moreover,we discuss the dependence relationship between the maximum WSF and the initial stepping angle,which indicates that the mosquito can regulate this angle to increase or decrease the WSF during landing or takeoff.These finding are helpful for uncovering the locomotion mechanism of aquatic insects and for providing inspiration for the design of microfluids miniature boats,biomimetic robots,and microsensors.