Developed System to Control Pump Feed Rate Based on Pressure on Lining Concrete (News Release)

FUDO Corporation (Headquarters: Shibuya-ku, Tokyo; President and Representative Director: Hiroharu Okumura; hereinafter referred to as "the Company"), a member of the Daiwa House Group, has developed a "Pump Feed Rate Control System" that smoothly and automatically places concrete by controlling the pump feed rate in response to the pressure applied to the formwork during the placement of lining concrete in mountain tunnels. The system was introduced in the "Hiroshima-Kure Road Kure Tunnel Construction" (Client: West Nippon Expressway Company Limited, Chugoku Branch) currently under construction by the Company in Kure City, Hiroshima Prefecture, and has been confirmed to enable labor savings of up to 50%.

*1. A movable form used when constructing lining concrete for tunnels.

Pump Feed Rate Control System

Background of Development

During the lining of mountain tunnels, concrete is typically placed alternately on the left and right sides of the formwork. When concrete is placed on only one side and the height of the placed concrete rises, the lateral pressure on that side can increase excessively, raising concerns about deformation or displacement of the formwork, leading to insufficient finished dimensions. Therefore, when pressure tends to rise, the concrete pump's feed rate is reduced to adjust the concrete discharge volume. However, these judgments and operations have traditionally been performed manually based on the experience and intuition of the workers.

Meanwhile, in the automatic placement of lining concrete, if pressure increases, emergency stops or other measures become unavoidable, which can interrupt the automatic placement and hinder the benefits of automation. To solve these challenges simultaneously, this system was developed.

System Overview

The system combines the Company's developed "Pressure Watcher®," which monitors the pressure status on the formwork in real-time during lining concrete placement to prevent poor filling and voids, with the "Tunnel Secondary Lining Automatic Placement Slide Form" developed by Gifu Kogyo Co., Ltd. (Headquarters: Mizuho City, Gifu Prefecture; Representative Director: Kunihiro Munakata), which automatically places lining concrete.

This enables continuous placement without stopping the automatic placement of lining concrete while monitoring and controlling pressure, contributing to construction management.

System Features

The lining work crew, normally consisting of six people per shift, can be reduced to four people through automatic placement. By combining this system, the need to monitor pressure and operate the pump is eliminated. This allows for a further reduction of one person, enabling a three-person crew and achieving 50% labor savings.

Future Development

We will continue to develop construction automation technologies, aiming for complete automation of lining concrete placement and further improvements in productivity, and will actively utilize them at our tunnel construction sites.

Construction Overview

Project Name: Hiroshima-Kure Road Kure Tunnel Construction

Location: Matsuba-cho to Nikawa-cho, Kure City, Hiroshima Prefecture

Client: West Nippon Expressway Company Limited Chugoku Branch

Contractor: FUDO Corporation

Construction Details: Tunnel length L=3,249m (Tunnel section L=2,376m)

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