A significant amount of water is lost in canals due to seepage. This could be saved to irrigate barren land. This article presents the measured seepage data by the inflow-outflow method on seven so-called concrete-lined distributary canals in Punjab, Pakistan. A special feature of the inflow-outflow method is the relatively long lengths of the canal reaches (9 to 5 km), which is the longest one could find in the literature so far. The seepage in canals is also calculated using five empirical formulae. The results show that the Swamee and the Punmia formulae performed admirably with mean percent errors of −20% and + 19% respectively. Moritz formula stood at +53% while Kostiakov scored +158%. The research also proposed a slight modification in the Swamee formula whereby, instead of the canal width, the surface water width was used in the calculation of the dimensionless variable F. This led to a beneficial effect of bringing down the percent mean error from −42% to −20%. K E Y W O R D S empirical formulae for seepage estimation, inflow-outflow method, lined distributary canals, seepage estimation, seepage loss RĖSUMĖ Une quantité importante d'eau est perdue dans les canaux en raison de l'infiltration. Cela pourrait être économisé pour irriguer les terres stériles. Cet article présente les données d'infiltration mesurées par la méthode entrées/sorties sur sept canaux de distribution dits en béton au Punjab, au Pakistan. Une particularité de la méthode entrées/sorties est la longueur relativement longue des tronçons du canal (9 à 5 km), qui est la plus longue que l'on puisse trouver jusqu'à présent dans la littérature. L'infiltration dans les canaux est également calculée à l'aide de cinq formules empiriques. Les résultats montrent que les formules de Swamee et de Punmia se sont admirablement comportées avec des pourcentages d'erreur moyens de −20% et + 19% respectivement. La formule de Moritz s'établit à + 53% tandis que Kostiakov marque +158%. La recherche a également proposé une légère modification de la formule de Swamee selon laquelle, au lieu de la largeur du canal, la largeur de l'eau de surface a été utilisée dans le calcul de la variable sans dimension F. Cela a * Analyse de la perte par infiltration des canaux d'irrigation revêtus de béton au Punjab, au Pakistan

An experimental program has been conducted to investigate the onset of Ledinegg instability in vertical down-flow. For three size uniformly heated test sections with L/D ratios from 100 to 150, the pressure drop under subcooled boiling conditions has been obtained for a wide range of operating parameters. The results are presented in non-dimensional forms which correlate the important variables and provide techx_iques _or predicting the onset of flow instability.

Empirical based approaches play an important role in tunnel excavation and support system design. These approaches are considered to be very effective in optimising the process of tunnel excavation and particularly tunnel widening. Several reliable empirical approaches have been developed, however the selection or utilisation of an appropriate empirical method for designing the widening of a tunnel is still a challenging task. Therefore, in this work, the analysis of seven different empirical design approaches was carried out to determine the rock mass behaviour during tunnel widening in high in-situ stress state. These approaches include New Austrian Tunnelling Method, Rock Mass Rating, Rock Mass Quality, Rock Mass Index, Rock Structure Rating, Geological Strength Index and Basic Quality Index. On the basis of simulated statistical results obtained from the said empirical approaches, it was found that the application of Rock Mass Quality approach is highly effective in the tunnel widening since it can satisfactorily incorporate the equivalent dimensions and in-situ stress condition of widened tunnel. The method furnishes optimised reinforcement and support design. Additionally, this study also produces reliable data related to the initial excavation of tunnel which can be helpful in defining precise rock mass parameters during tunnel widening.

Most of the tunnel excavation methods involve the use of explosion and vibration techniques that is not feasible in urban areas due to unavoidable production of noise, vibration, and dust. The environmental considerations of tunneling projects in urban areas demand the use of excavation methods in which minimum noise, vibration, and dust is produced. In this study, non-vibrational rock splitting method is introduced that involves the fragmentation of rock segments using a split-wedge system inserted into already drilled boreholes. The main objective of this study is the investigation of important parameters involved in the non-vibrational rock splitting method for improving its efficiency. Discrete element analysis of this method was performed using Particle Flow Code (PFC 2D) and the concept of Representative Elementary Volume (REV) was used to simulate intact rocks based on their unconfined compressive strength and modulus ratio concept. Maximum borehole spacing values were obtained using the numerical simulation of rock splitting process in intact rocks. The numerical analysis results show that increased borehole spacing values can be used for all intact rock types in cases of average modulus ratio and high modulus ratio and also that decreasing the borehole depth generally results in the use of increased borehole spacing.

The paper focuses on the improvement of the clayey soil (A-6) with the locally available and cheap modifiers, in terms of stiffness behavior of the weak subgrade soil for flexible pavement. The modifiers used include lime (hydrated), marble waste and sand. The soil specimens underwent triaxial testing and Clegg impact testing. Triaxial testing involved the assessment of the resilient modulus (MR) and impact testing using the Clegg Impact Hammer. According to the study, lime proved to be the most influencing modifier as it improves the stiffness of the weak soil better than other modifiers. A quite accurate statistical relationship between the MR and the variables (including Clegg Impact) involved in the testing procedure has been established