At Construction Department, in addition to general slope countermeasure engineering work such as landslide prevention engineering work, we also undertake excavation of underground water wells and construction of environmentally friendly spraying / non-sprinkling snow melting facilities that effectively utilize underground water and geothermal heat. In terms of technology development in recent years, we have developed "Karuwaza Sakkun", a simplified drilling system that is very useful for preventing sediment disasters in housing development land and at the sites where there is urgency such as slope disaster sites. The salient feature of this method is that it allows doing quick drilling at relatively low cost at the places where the drilling depth is relatively shallow or at the places where transportation and installation of drilling machinery is difficult because of space etc.
Based on the characteristics of land, we take into consideration the natural environment such as ecology and natural landscape, and we strive to further improve our technical capabilities in the rapidly changing technological innovation, and respond to the requirements of the times with our robust system and mobility.
Landslide prevention work includes suppression work that suppresses landslide fluctuation by changing natural conditions such as topography and groundwater, and deterrence work which deters landslides by directly adding resistance force to landslide lumps that tend to slide by using structures such as steel pipe piles and anchors.
As suppression work, in addition to horizontal drilling work to excavate shallow groundwater, we drill water collecting wells, and we perform drilling work to remove groundwater from the water collecting wells. Moreover, we also perform head excavation work for removing the load of the landslide head and terminal embankment work that constructs embankment at the end of landslide.
As deterrent works, we perform anchor work which utilize tensile strength of steel material fixed to a base to counteract a landslide, and steel pipe pile work that directly resists sliding by inserting steel pipes to immovable ground to add shear resistance force and bending resistance force to landslide.
The purpose of the slope surface protection work is to stabilize the slope by treating the surface of the slope that appeared because of cutting and embankment work.
In the slope protection work, we sow plants on the cut and embankment slope surface, and when required, we develop greenery on the slope surface that would maintain stability of the growth foundation and maintain and manage the vegetation that is cultivated. In combination, we also perform slope protection work based on structures such that grating crib work, mortar and concrete spraying work, and reinforcing bar insertion work, protection work with structures and protection work with plants.
Well drilling work refers to hole drilling by using the drilling machinery.
As well drilling work, we conduct excavation of wells for snow removal and well excavation for use in agricultural water. In addition, we are also engaged in drilling of heat extractors for melting snow on walkways by using geothermal heat and drilling of wells for melting snow without sprinkling water.
Grout engineering work is a method of infusing injection material (grout) that is solidification agent into underground cracks, gaps, cavities, and within or around the structures. This is mainly undertaken for the purpose of waterproofing or strengthening of the ground or integrating the structures.
Survey Design Department conducts surveys and designs for a wide range of requirements such as efficient and reliable maintenance of social infrastructure such as roads and rivers, and renewal and upgrade of aging facilities.
Meanwhile, we conduct field survey, monitoring, observation, proposing and designing measures and techniques with respect to slope failures and falling rocks caused by heavy rain and earthquakes, which are increasing in recent years, and in this manner, we are working towards developing safe and secure social infrastructure.
In addition, we provide services with high technical capability regarding stock inspection, diagnostic survey, and renewal and upgrade design of social infrastructure that has become old and that are due for renewal and upgrade.
We will continue to provide services that meet the changing social requirements by further improving our excellent technical expertise built through years of experience.
We will grasp the behavior of soft ground and look into the appropriate measures.
In order to grasp the amount of settling of soft ground and the time required for consolidation, it is necessary to shed light on its properties and characteristics. In addition to the drilling survey, we collect samples from the ground without disturbing the target soil and conduct indoor soil tests. Even when it is difficult to collect samples, it is possible to analyze from standard values etc. On the basis of the analysis results, we propose an appropriate soft ground countermeasure work.
For cut and embankment slope surfaces, natural slopes, rivers, etc., we propose construction methods that can deliver continuous benefits at reasonable costs with feasible technologies with respect to the anticipated operations.
In order to shed light on the circulation mechanism of water in the target area and its quantitative evaluation, it is necessary to understand information on the flow of water. We measure the groundwater level, flow direction and flow rate for obtaining more detailed groundwater information.
We propose landslide monitoring and emergency measures. We propose landslide monitoring and emergency response steps for unstable slopes after the landslide has occurred or where symptoms of landslides are seen. If necessary, we rush to the site of large-scale disaster, and summarize the findings concerning the occurrence mechanism and emergency measures etc.
As a geological survey of building foundation, slope surface, landslide site etc., we conduct exploratory drilling, horizontal loading test in the hole, simple bearing force measurement, cone penetration test, Swedish weight sounding test, etc.
At Disaster Prevention Department, we are mainly engaged in landslide related business. Landslides are often caused by earthquakes and abnormal weather conditions such as snow melting and heavy rain. Landslides affect people's homes, roads, rivers, farmlands, forests, etc., which will have a huge impact on people's lives. We prepare survey plans for landslides, conduct surveys and analysis, design countermeasures, prepare working procedures for preventing landslides, and offer advice for ensuring safety during work. As for the steps to be taken after the occurrence of landslides, we propose appropriate monitoring systems and software measures if there is a risk of expansion of damage.
In addition, we have the experience of assisting in preparing the documents related to applications for designation of landslide prevention area, preparing the documents for determining landslide occurrence, and procedure for designation of sediment disaster prone area based on the Sediment Disasters Prevention Act. In recent years, we also conduct inspection work for maintaining and managing landslide prevention facilities, and planning and designing renewal and upgrade work for aging of facilities.
We conduct sand erosion control surveys in mountain streams and surveys in landslide areas.
In the case of developing landslide occurrence forecast and warning evacuation system, and designing preventive works through stability analysis of slopes, it is necessary to determine the mechanism of occurrence of landslides and characteristics. Therefore, we survey the topography, geology, groundwater, and landslide behavior in the landslide areas. Landslide surveys include surface geological survey, drilling survey, borehole camera survey, groundwater logging, groundwater tracking, soil quality test of sliding surface, and observation of landslide dynamics;.
We design slope countermeasures such as horizontal drilling work, drilling of water collecting wells, steel pipe piling work, anchoring work, pressing embankment, earth removal work, and slope protection work as steep slope countermeasure.
We study the mechanism of occurrence of landslides based on the landslide block classification, position of the sliding surface, soil mechanics properties, groundwater condition, etc. In addition to identification of the destabilized slopes by earthquake response analysis based on the anticipated earthquake motions, creation of geological evolution map utilizing three-dimensional data, landslide collapse simulation, and groundwater analysis, we also conduct three-dimensional model analysis by using GIS.
We inspect soil erosion control facilities, landslide prevention facilities, and slope protection work, and we prepare plans for increasing the life span of facilities and we suggest the methods of maintaining and repairing such facilities.