## 1 Introduction
The major advantages of the enhanced techniques for monitoring and measuring geosynthetic structural performance and the in-soil geosynthetic response include (1) the early detection of initial damage to prevent the sudden collapse of civil structures and the associated loss of lives and money; (2) the extraction of current operational data, which has many benefits in various areas of smart city management such as transportation and traffic flow monitoring; (3) substantial cost savings in major projects by decreasing uncertainties and thereby minimising the design safety factors and by accelerating construction to exploit real-time response data gathered from infrastructure under construction; (4) the advancement of more-accurate and in-depth structural performance knowledge during construction and about lifetime service capacity and extreme loading conditions such as natural hazards; and (5) the use of field-scale databases as a valuable resource for developing validated analytical and numerical models that can be used to enhance the reliability and cost-effectiveness of current design methods and develop more economical, safer, and performance-based design approaches [3; 12; 13; 14]. Infrastructural health monitoring is particularly paramount in supporting critical structures in urban areas and along transportation corridors or in protecting the environment from hazardous waste, fuel leakages, or other contaminants [15; 16; 17]. However, despite extensive developments in designing, manufacturing, and testing geosynthetics, other geosynthetic vital aspects including sustainable development, health monitoring, and instrumentation have attracted comparatively little attention [3]. Indeed, sensor-integrated, optical fibre-based, and self-sensing piezoresistive-based multifunctional geosynthetics are the only efforts and technologies developed to achieve smart geosynthetics. However, there is still a lack of applicable smart geosynthetics with high field performances, compatibility with geomaterials, high resistance of sensing technology against aggressive factors, a simple production process with a low cost, minimum complementary systems, and environmental friendliness. Additionally, there are few or no comprehensive review papers attempting to address the aforementioned concerns in the way that is explained above. Accordingly, in this paper, various intelligent geosynthetics based on different diagnosis technology were critically reviewed to bridge the existing knowledge and to achieve the best concept and technique for the development of a practical smart geosynthetic. \begin{table}
\begin{tabular}{c c} \hline \hline
**Property** & **Specification** \\ \hline General characteristics & Thickness, material type and manufacturing, specific gravity, mass, roll dimensions, polymer(s), absorption \\ Index specifications & Strip tensile strength, flexural strength, burst strength, shear modulus, creep resistance, Poisson’s ratio, puncture resistance, cutting-trapezoidal tear strength, penetration, flexibility (flexural strength), grab strength \\ Endurance specifications & Chemical resistance, ultraviolet (UV) stability, wet/dry stability, temperature stability, biological resistance, long-term durability, abrasion resistance \\ Performance–fabric/soil specifications & Stress–strain, cyclic and dynamic loading, friction/adhesion, soil retention, creep, filtration \\ Hydraulic specifications & Soil retention, porosity, apparent opening size, permeability/ permittivity, clog resistance, open area percentage, in-plane flow capacity \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Required features of geosynthetic materials. Moreover, the manufacturing processes, theoretical research, materials, and methods that have been employed to date for developing smart geosynthetics were discussed. Different applications of smart geosynthetics in several monitoring systems were reviewed.