Abstract: Disclosed are a shield tunnel segment structure and a construction method thereof. The shield tunnel segment structure includes segment blocks sequentially spliced in a circumferential direction. Each segment block forms a closed annular segment structure, and outer diameters of adjacent annular segment structures gradually increase in an axial direction. At least two adjacent segment blocks of the same annular segment structure form an annular inner groove, and at least one segment block of the adjacent annular segment structures is provided with an inner bump which matches the annular inner groove. At least two adjacent segment blocks of the same annular segment structure form an annular outer groove, and at least one segment block of the adjacent annular segment structures is provided with an outer bump which matches the annular outer groove. The annular outer grooves and the annular inner grooves are staggered in the circumferential direction.

Abstract: An extension ladder assembly having an anti-slipping mechanism is provided. The extension ladder includes a master ladder, a slave ladder, a pulley, a locking mechanism, the antislipping mechanism and adjustable ladder feet. The master ladder and the slave ladder are each composed of two posts and several rungs. The master ladder and the slave ladder are each composed of two posts and several rungs. The master ladder is slightly wider than the slave ladder. The anti-slipping mechanism prevents the slave ladder from being tripped and slid down, thereby safeguarding the safety of a user of the ladder. The pulley and the locking mechanism make the extension ladder suitable for various height requirements on work sites. The adjustable ladder feet make the extension ladder stand firm and secure by fine and minor adjustment of angles to accommodate different surface or ground conditions the ladder is placed upon.

Abstract: An extension ladder assembly having an anti-slipping mechanism is provided. The extension ladder includes a master ladder, a slave ladder, a pulley, a locking mechanism, the antislipping mechanism and adjustable ladder feet. The master ladder and the slave ladder are each composed of two posts and several rungs. The master ladder and the slave ladder are each composed of two posts and several rungs. The master ladder is slightly wider than the slave ladder. The anti-slipping mechanism prevents the slave ladder from being tripped and slid down, thereby safeguarding the safety of a user of the ladder. The pulley and the locking mechanism make the extension ladder suitable for various height requirements on work sites. The adjustable ladder feet make the extension ladder stand firm and secure by fine and minor adjustment of angles to accommodate different surface or ground conditions the ladder is placed upon.